Sulphuric acid was once known as the "oil of vitriol" and that's a fitting name. In Cambodia, scores of people have used it, and other highly potent acids, in malicious revenge attacks.

The acid dissolved Chheav Chenda's clothes, in hissing steams of vapour. She found herself standing naked, dazed and in shock, on a dusty street of Cambodia's capital with Malita crying beside her. Some of the acid had splashed the girl, too, scarring and disfiguring her for life.

Chheav Chenda's attacker had stopped to gawk and now stood there grinning as he watched the young woman trying to cover herself with her arms. He threw the empty container contemptuously in front of her, got back on the motorcycle and rode away with his accomplice.

As bystanders rushed to her aid, Chheav Chenda lay down under a tree and closed her painful eyes. She would never see again.

"I'll never forget his face," she says. "He stood there and laughed."

Since the first recorded case, in 1964, an estimated 414 Cambodians have fallen victim to acid attacks, 25 of whom died as a result, according to the Cambodian Acid Survivors Charity (CASC), set up in 2006 in Phnom Penh. It is likely many other cases have gone unreported, however. A sixth of the victims have been children under the age of 13, usually unintended casualties during attacks on their parents.

"An acid attack could be the result of a dispute between families, or perceived infidelity, or an argument over money," says American social worker Erin Bourgois, who is a project manager at CASC. "Almost a third of the victims don't know why they were attacked."

Chheav Chenda knows. It was her philandering husband's long-time French-Cambodian lover and business partner, she says, who hired local men to "punish" Chheav Chenda for her spouse's continued affection for her.

"My husband warned me to be careful, but I did not take it seriously," she recalls. "I did not believe she would do something like this to me."

Survivors of acid attacks suffer horrible disfigurement and lasting health problems. And as if that wasn't bad enough, they also face a lifetime of neglect, ostracism and penury as they are shunned by society.

That has been Chheav Chenda's fate. Once she lived in a comfortable home with three beautiful young children and a promising future. Today, the 39-year-old lives alone with Malita in a grimy concrete cuboid in a nook of a narrow, winding dirt path in a squalid Phnom Penh shantytown, surrounded by domestic violence and destitution.

Outside one nearby wooden shack, bare-chested men sit on a bamboo platform over a fetid puddle, drinking beer and eyeing the visiting foreigner suspiciously. Near another, a teenager is sniffing glue from a plastic shopping bag. All around, grubby children, many of them naked, crawl and scamper about in the mud on rubbish-strewn patches of land.

Yet even here Chheav Chenda and Malita are often treated as outcasts.

"People avoid us, but we've learned to live with it," Chheav Chenda says. "Even my sister and brother have abandoned me. They're ashamed of me [because of her disfigurement]."

Soon after the attack, her husband left Chheav Chenda, taking with him their two elder children.

"I'm sad because my father never comes to visit me," says Malita. "He has moved to a new house so his neighbours won't know about us."

A prematurely brooding nine-year-old, she rarely smiles and never goes out without her floppy hat, which hides the large bald patch on the top of her head where the acid burned away her hair. The hat's broad, drooping rim also helps conceal the thick burn scars that loop around her eyes and down her cheeks.

On the otherwise bare walls in the dimly lit home hang a couple of framed pictures that show Chheav Chenda before the attack: an attractive woman with delicate features, almond-shaped eyes, arched eyebrows and plump lips.

All have been erased or mangled by the acid, which remoulds skin like Play-Doh, twisting, bunching and knotting human features into cruel new shapes and arrangements. Noses get flattened, ears shrivel up or collapse, chins become gnarled lumps, eyes turn into white balls without lids and lips become hideously swollen and deformed. In extreme cases, faces take on an almost reptilian quality.

Chheav Chenda suffered second- and third-degree burns on about 40 per cent of her body: her neck, chest, stomach, shoulders, arms and thighs all were horribly ravaged.

She ekes out a living tying rice bags for US$3 a day whenever she feels strong enough to work. Even that job she could only get with the help of a foreign charity, as no one wants to employ a frail and blind woman, she says.

"I still haven't come to terms with my situation. Why did this happen to me? I was a good person. I didn't deserve it," Chheav Chenda laments.

"I wanted to die," she admits. "But I thought, 'If I die, who will look after Malita?'"

Her daughter is sitting on the concrete floor with her friends Meng Chou, 10, and her four-year-old sister, Panha. Malita's friends, too, have seen more than their fair share of brutal violence. In a jealous rage, their father doused their mother with gasoline and set her alight inside their home, a neighbouring shack. The woman suffered third-degree burns but survived.

In one of those eerie coincidences that pass for cruel irony, the Eminem and Rihanna song filters through the tiny, barred window of Chheav Chenda's home. The lyrics, "Just gonna stand there and watch me burn/ But that's alright because I like the way it hurts", intrude inappropriately, but luckily the girls remain oblivious to their meaning.

Malita studies at a school for disadvantaged children run by a foreign NGO and hopes to become a nurse or doctor.

"I want to help other people like us," she stresses.

For the first time Chheav Chenda smiles.

"What acid survivors need most is the motivation to start over," says Sunchan Soksan, a social worker for CASC. "Some of them don't value themselves and their lives. They're rejected, neglected and ignored in their communities, so they become despondent and withdrawn."

Often, no sooner have acid-attack survivors emerged, badly scarred but alive, from long painful treatment than they find they have turned into social pariahs, shunned by relatives, friends and strangers alike. Some of them try to hide their face with a , a type of multipurpose Cambodian shawl, whenever they venture out in public. Others rarely venture out at all.

"There's a stigma to disfigurement in Cambodia," Sunchan Soksan says. "Many people assume that acid victims must have done something bad to deserve it."

Net Sotheanim admits to having assumed exactly that. As CASC's legal officer, the 27-year-old has been working tirelessly for years to help acid-attack victims get justice in Cambodia's often sclerotic criminal courts. While doing so, she's had to reexamine her own views.

"Even I used to believe that acid-burn victims deserved it for having done something wrong, like being unfaithful to their partner or spouse," Net Sotheanim says. "It was only when I got to know them better that I realised how badly they have been mistreated and victimised.

"Often, when people learn I work with acid victims, they tell me I shouldn't because they are bad people. Even a professor of law told me that!"

It was largely thanks to CASC's relentless lobbying that, two years ago, Cambodia passed the Acid Law, which imposes harsher penalties on the instigators and perpetrators of attacks. Previously, they only faced charges of "intentional violence", with relatively lenient sentences, whereas now they face 10 years in prison and a fine of US$5,000, a fortune in the impoverished country. Acid-attack victims are now also entitled to financial compensation from their attackers.

Another new law regulates the sale, storage, transportation, packaging and use of all potent acids across the country.

But there's a long way to go yet in getting the law universally enforced and holding perpetrators to account. Of the 43 legal cases CASC has worked on, in only 11 have the perpetrators been sentenced. The charity is monitoring the progress of another nine protracted cases in the country's courts, but it sees the 11 convictions as welcome progress.

"Survivors want justice and now more of them can get it," Net Sotheanim observes.

What many of them want even more than justice is the chance to fit in.

"Yesterday, when I went to the market, people stared at me," says Khat Thrim Waew, a vivacious 18-year-old who became badly disfigured as a baby during an acid attack on her family. "People always look at me."

The teenager's face is covered in thick, leathery scars and the lens in her useless right eye is milky and clouded. Yet one of her habitual smiles always lies in wait to transform her features into a picture of youthful exuberance. She laughs just as readily - a delightful, bubbly laugh with a perfect set of pearly teeth that lightens up the atmosphere in an instant.

Recently, the young woman underwent extensive reconstructive surgery at Hong Kong's Queen Mary Hospital, thanks to her benefactor, Geraldine Cox, an Australian philanthropist who runs Sunrise Children's Village, an orphanage in Kandal province, near Phnom Penh, where Khat Thrim Waew has lived since the age of 10. The hospital's surgeons have restored her mouth and deformed ear with skin grafts. She now feels much more confident about her looks.

Nevertheless, "some people call me a 'ghost'. They see me as a monster", Khat Thrim Waew says, in fluent English, which she's learned in lessons at the orphanage and at the private high school she attends. "But I don't mind. I've gotten used to it."

When Khat Thrim Waew was three years old, her mother sold her to a begging ring that took her across the border to Thailand. She was used as a human prop beside an elderly woman who begged from tourists on the streets of Pattaya. Criminal syndicates in Cambodia often prey on badly disfigured children, snatching or buying them from their parents and forcing them to beg on the streets, soliciting sympathy from passersby.

But those days are behind Khat Thrim Waew. She has plenty of friends at the leafy, well-appointed orphanage, which is also home to children with polio, cerebral palsy, brittle bone disease, hepatitis and Asperger's syndrome.

"She's terribly disfigured, but she has an indefatigable spirit," Cox says. "I tell her she's beautiful."

That they are beautiful is not something most acid-attack survivors ever get to hear. Faced with widespread prejudice, many end up blaming themselves for their predicament.

"It was my karma for what I did in my past life," insists Sok Thy, 59, a motorbike taxi driver who lives in a village in Kandal.

He's referring to the Buddhist concept of causality, which attributes suffering and misfortune in this life to presumed misdeeds in past ones.

Sok Thy, a bicycle repairman, became the victim of an acid attack in 1994 when, he says, a cousin decided to settle scores over a business deal gone wrong. His relative, Sok Thy says, crept up on him as he lay sleeping on a mat outside his hut and poured battery acid over him.

"I realised at once what he'd done," Sok Thy recalls. "I ran inside and jumped into the large vat of water [in the bathroom]. I knew I'd lose my right eye." He used his other eye to look in the mirror and recoiled in horror. "I didn't recognise myself. It was like a ghoul was staring back at me. I was afraid of myself," the father of seven says.

Much of his face has melted into a smudged, knobby mask, with his right eye a blindly staring lidless bead and his right ear a misshapen button with a hole in it. The knotted scars continue down his neck and cover his chest in rivulets of mutilated epidermis.

He was in agony for weeks, and payment for his medical treatment drove his family into penury. Sok Thy took to begging from tourists outside Phnom Penh's Tuol Sleng Genocide Museum, a one-time high school turned Khmer Rouge prison where some 17,000 Cambodians were executed and tortured to death during the Maoist movement's brutal reign, between 1974 and 1979.

He wouldn't be shy about it, either. He would accost tourists, with his cadet hat in hand, thrusting his disfigured face in front of them and following the startled visitors around with repeated pleas for help. He earned more than US$10 a day, he boasts.

"My children needed me to support them," he says.

Cambodia offers little in the way of social security, so the poor, especially those who are disabled and unskilled, often survive any way they can.

"If you don't help yourself, no one will help you," Sok Thy says.

One day, Sok Thy says, he found a purse with US$3,000 in it.

"I could hardly believe it," he says, as his youngest daughter, nine-year-old Davin, snuggles up to him inside the family's Chinese shophouse-style home.

With the money Sok Thy bought an old Honda motorbike to start a two-wheeled taxi service. He's continued begging on and off, to supplement his meagre earnings.

Recently he developed a lung tumour from having inhaled noxious traffic fumes all day long for years. Sometimes he coughs up blood. But it could have been worse, he observes stoically.

"I have my family and my wife has stood by me. Many acid survivors don't have anyone."

Like most perpetrators of acid attacks, Sok Thy's attacker was never prosecuted. For a while, he says, he fantasised about revenge, but in the end decided against it. All his life he'd been witness to savage violence and he did not think more of it would solve anything.

Sok Thy lived through the Vietnam war, which saw large swathes of Cambodia carpet-bombed by United States forces in an effort to root out Viet Cong guerillas; he endured the vicious Khmer Rouge period, during which some two million Cambodians perished on Pol Pot's "killing fields"; and he made it through the country's bloody civil war, which raged in the 1980s.

"Many Cambodians have witnessed extreme forms of violence in their lives and have become either traumatised by violence or inured to it," Bourgois says. "In many ways this is still a violent country and acid attacks are one form of violence."

And they can take shockingly brutal forms.

Deb Da was nine and fast asleep next to his mother, a widow, in their simple home in Kampong Cham province, in eastern Cambodia, when he awoke to his mother's screams. Two men were holding her down as a woman, a neighbour Deb Da knew well, was forcing some kind of liquid down her throat.

It was probably hydrochloric acid, which locals use for processing latex and is widely available in the province, a heartland of rubber plantations. People are known to have committed suicide by drinking it.

"I started crying," Deb Da, 26, recalls. "The woman turned towards me and splashed me in the face with the acid to make me stop."

His mother, whom the neighbour had suspected of having an affair with her husband, died within minutes before Deb Da's eyes, leaving him and his brother orphaned.

"Most of my friends turned their backs on me," Deb Da remembers. "That hurt me."

He lived with relatives before moving into an orphanage.

A soft-spoken man whose handsome features are veined with dense capillaries of scars, Deb Da is employed today as a security guard at the CASC shelter.

The charity provides free surgical care, physiotherapy, counselling and financial support for victims across Cambodia. At its regular group meetings, survivors gather at the shelter for meditation sessions, karaoke nights and social events. They also come to discuss their hopes and troubles with people who best understand them: "Who better to know what they've been through than others who have been through the same?" Bourgois notes.

The charity has been conducting nationwide outreach programmes to educate locals about the dangers of acid attacks and to help them see the world through the eyes of the survivors.

"We want people to look beyond the scars and see the person beneath," Bourgois says.

CASC's prevention campaign and the new Acid Law appear to have been highly successful. Whereas in 2010 there were 27 documented acid attacks in the country, this year there has been only one so far.

Its victim, 42-year-old Hak Ay, sits on a bed in a ward of Phnom Penh's Children's Surgical Centre, which offers free care to disabled youngsters and is one of the few places in the country equipped to treat acid burns. Surrounded by visibly sick children, whose relatives have bunked down on mats laid on the floor around their beds, Hak Ay strikes a solitary figure.

"My wife did this to me," he says, laconically.

He speaks with difficulty as pain engulfs his body and is kept in check by powerful analgesics and sedatives.

Hak Ay says he was sleeping in a hammock under his house on stilts in Banteay Meanchey province, in northwest Cambodia, on April 22 when his 26-year-old wife poured acid over him after a domestic dispute. She has been arrested and will soon be sentenced under the Acid Law.

The construction worker suffered extensive second-degree burns to his face and upper body. Much of his skin is inflamed with thick reddish scars, which, on his chest and torso, comprise a flow chart of acidic ruin and a permanent reminder of that fateful day.

He has had five rounds of surgery, including one aimed at fashioning eyelids from skin grafts. He has blurred vision in both eyes and may yet lose his sight. He is facing years of treatment, rehabilitation and physiotherapy.

"We focus on restoring functionality. Aesthetics come second," says Dr Keo Vanna, head of the Children's Surgical Centre's reconstructive surgery unit, who has treated numerous acid-attack survivors, young and old.

Among Keo Vanna's patients have been a fisherman, attacked by his mates with acid on a boat in Thailand, whose mouth shrank to a penny-size hole, through which he had to suck liquid food with a straw before surgery helped widen the orifice. Another victim the doctor has treated had had his chin fuse to his chest, causing his head to tilt forward and his mouth to stay agape with the tongue lolling out.

Yet, a long series of surgical procedures can feel like torture and some patients flee the hospital and refuse further treatment.

"Sometimes their disfigurement is so severe that they barely seem human," Keo Vanna says. "Even I, as a doctor, feel daunted by [the surgery needed]. But acid victims are very grateful patients. They come and hug me."

Acid attacks show both the best and worst sides of Cambodians, the doctor observes: the stoic resilience and graceful spirit of the victims and the callous brutality of the perpetrators.

"I had a patient, a mother, who was breastfeeding her baby when she was attacked," Keo Vanna says. "Both of them went blind. Imagine that! Imagine doing something like that!"

Chheav Chenda doesn't need to imagine such brutality.

"When someone does this to you, a lot of you dies inside," she says. "But you have to keep on living. You cannot give up. You must not let them kill you twice."