Behind bars, you have to be strong, you have to be tough - and now, in Ventura County, you have to be brief.

Following a national trend in jail mail, authorities are requiring that inmates send and receive only postcards.

Over the years, contraband of all kinds has made its way into the facility in "innocent-looking letters," jail officials said. Razor blades, drugs and coded messages from gangs have been snuck in between the sheets.

"We have to take the stamps off envelopes because they'll put drugs on the back that inmates will then be able to lick," said Cmdr. Brent Morris, who runs one of the county's two jails. "It gets very cumbersome."

As of Oct. 4, letters other than those from lawyers will be marked "return to sender." The same goes for postcards with racist references, obscenities, nudity, gang symbols and, under the new rules, "any perceived biohazard (i.e. lipstick, gloss, scents, etc.)."

Cash-strapped local officials in at least seven states have instituted similar postcard-only policies, in part to cut down on the staff time required to open sealed envelopes. One of the first was Maricopa County, Ariz., Sheriff Joe Arpaio, the self-styled "toughest sheriff in America" who runs a famously spartan jail in Phoenix.

An inmate representing himself sued Arpaio over the restrictions and lost. But American Civil Liberties Union lawsuits filed over the last two months in Florida and Colorado have yet to reach court.

"There's no question that this is a serious abridgement of the 1st Amendment rights both of detainees and people on the outside who want to correspond with them," said David Fathi, the Washington, D.C.-based director of ACLU's National Prison Project.

In a lawsuit filed against officials in Boulder County, Colo., ACLU attorneys pointed to a number of inmates whose freedom of expression would be "chilled" by the mail restrictions. There was a man who wanted to discuss a sensitive medical condition in a letter to his former doctor, and another who didn't want his children to see private messages intended for his wife. Others didn't want to draw attention to their stints in the slammer. That's particularly tricky for Colorado Springs inmates, who must use jail-issue postcards that feature a color photo of the jail.

"Most people in jail are pretrial detainees who haven't been convicted of anything," said Fathi. If they had been able to make bail, he said, they'd be at home - still charged with a crime but able to send all the letters they want.

In Boulder County, the switch to postcards was prompted by two sex offenders who were seeking pen-pal friendships with young girls. But in Ventura County, no single incident triggered the change.

Morris said that jail officials followed the emerging policy elsewhere through professional associations. They saw it as a way of both cutting security risks and freeing up staff. Two employees now spend most of their shifts sorting through mail flowing to and from 1,500 inmates.

"When you balance it with the challenge of budget and staffing, it seemed like a prudent thing to institute," he said.

But for Los Angeles County, the tradeoff isn't worth it, said Steve Whitmore, a spokesman for the Sheriff's Department.

"We believe the mail coming to inmates is as important as their phone calls," he said. "If we were to limit the mail, we believe we would see a rise in mental challenges, maybe even violence."