SACRAMENTO (AP) — California uses a controversial method to recover contraband from inmates believed to have swallowed it or concealed it in body cavities: “potty watches” where inmates are handcuffed and shackled for days or even weeks while guards watch around-the-clock until nature takes its course.

Prison officials say the watches are necessary to recover weapons, cellphones and notes passed among inmates to coordinate illegal gang activities. Some recovered items seem truly bizarre: a can opener, hearing aids, and an entire electric tattoo kit.

The watches have been used 1,200 times in the last 2½ years, yet state reports show that they produced results less than 41 percent of the time. Other large states have far less restrictive ways of searching for contraband.

“It was the worst two weeks of my life,” recalled Raymond Kidd, who was on contraband watch at Folsom State Prison for 13 days 2011 that found nothing. “I had to be duct-taped and gift-wrapped and shackled, 24-7, even while I slept.”

The Department of Corrections and Rehabilitation’s inspector general reported procedural problems this spring in nearly half of the contraband watch cases his office reviewed.

Suspected smugglers are strip-searched, then placed in an isolation cell in which the toilet has been covered and the water turned off. Their clothing is taped shut at the waist and legs to prevent them from physically reaching body cavities, their hands are cuffed to a chain around their waist and their legs may be shackled. If they fight back, they can be strapped down by the arms and legs. What are known as “hand isolation devices” — similar to oven mitts — can be used with a warden’s approval.

There they stay for at least 72 hours or until they complete at least three closely watched bowel movements and a guard searches through the results. Something is recovered from about four out of 10 inmates.

“It’s a fairly low percentage and people who aren’t guilty are being put through torture,” said Laura Magnani, an American Friends Service Committee program director who sits on a committee that mediates between the prison system and inmates. “I mean, people are shocked when they hear of this.”

Inmates are restrained to keep them from re-swallowing items and it is the inmates who can prolong the process by refusing to eat, department spokesman Jeffrey Callison said.

“We still have to have some way to determine if inmates have something in their bodies or they don’t,” Corrections Secretary Jeffrey Beard said in an interview. He said the department has reduced the number of watches in recent years and is exploring scanning technology that could one day replace them.

California’s current practice goes well beyond those of other states.

Texas, with the nation’s largest state prison system, and Florida, which closely trails California’s inmate population, along with Michigan, keep inmates who are suspected of swallowing contraband isolated for no more than 48 hours in a cell with the water turned off. Illinois and Georgia wait until inmates have one bowel movement, while New York waits for two. Ohio inmates can be kept in the cell up to seven days. The states would not disclose how often contraband is found.

California is the only state to chain inmates while they are in isolation cells, and its watches can last two weeks and longer — one stretched 52 days in 2013 before the inmate was transferred to a psychiatric hospital.

Kidd said his girlfriend was chewing gum when he kissed her in the visiting room; guards watching on a video screen suspected she had passed him a balloon full of drugs that he swallowed during the kiss.

Eating with both hands chained to his waist “was a circus act. It was a game of maneuvering the best you could to get your hands to your mouth,” he recalled. In the end, guards found nothing.

The watches were upheld by the 9th U.S. Circuit Court of Appeals last year in a decision authored by Appellate Judge Jay Bybee. Critics note that Bybee previously was a high-ranking U.S. Justice Department lawyer who helped write memos authorizing CIA interrogators to use waterboarding and other harsh tactics on terrorism suspects.

One judge dissented in part, saying restraints and brightly-lit cells could cause unconstitutional sleep deprivation.

State rules now call for providing a mattress and blanket and dimming the lights at night, if guards can still see the inmate. Guards are supposed to avoid applying duct tape directly to an inmate’s skin and are to periodically free hands and legs, one at a time, for five minutes of exercise.

The changes are a positive step, said Caleb Mason, the lawyer who lost in the 9th Circuit decision. But he said failing to find contraband 60 percent of the time “is a good reason to discontinue the procedure, given the extreme invasion of human dignity that is involved.”