DENVER -- These days it seems cell phones are about as common as women's shoes or men's ties. And like those shoes and ties, cell phones may be replaced fairly regularly.

The trouble is that old cell phone contains personal and sometimes sensitive information -- the kind that can do you harm long after the phone is in someone else's hands.

And it's a bigger problem than you might think because 80 percent of cell phones have data intact.

Whether you trade them in to your cell phone company or give them away to charity, cell phones are treasure chests, holding valuable information that is difficult to erase. Cell phones are like small computers, holding sensitive data that could leave you vulnerable.

"I kept a lot of personal information as well as business banking information," said cell phone user David Levi King.

When King's cellular phone stopped working, he exchanged it for a new one. But first, he reset the phone to wipe off all his personal information.

"When I got the new phone I deleted the information on my old phone, sent it back, then waited and later got a call," said King, who lives in Highlands Ranch.

The call came from Joanne Bishop in Los Angeles.

"It was a semi alarming phone call," he said.

It was alarming because his phone, the one with all the data supposedly erased, ended up in Bishop's hands after being refurbished.

Bishop had access to King's account numbers, personal contacts, usernames and passwords.

"I got so much information. I was hesitant to look at it because it felt like I was looking into someone's private life," Bishop said.

King said he expected his wireless company to make sure all that was gone before giving it to someone else.

"If you donate your phone or you are sending it back to your provider as a trade, there is a process for them to clear it for you, but any process can fail. If you want to make sure the data is off there, you should do it yourself," said Erik Larkin at PC World.

He said erasing information is not an easy feat with some of the more advanced phones.

"You may have to go through eight different steps to clear all the data on there," Larkin said.

And just removing the Sim card may not keep your information from landing in someone else's hands.

Luckily for King, Bishop was honest.

"In theory, they could have logged on, used my credit cards, stole my identity, opened accounts. There is a lot of things a dishonest individual could have done," King said.

King said he followed all the steps in the manual to erase his information and his cell phone company, Cingular, said it was a software problem they were having with his specific phone, an issue that has since been corrected.

But it it's not likely this was just an isolated incident since Bishop actually received another refurbished phone with yet another man's information on it.

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