CHECK THE BOX Thanks to recent anti-junk-mail awareness, utility companies, creditors, and other businesses now provide an opt-out box in the corner of monthly bills. Checking it should get you off the companies' own rent-sell lists. For bills without such a box, simply write "Don't rent or sell my name" on the top of the bill when you pay it.

DON'T JOIN BUYERS' CLUBS When your card is swiped through the register, your name and address can be linked to your purchases and your buying habits tracked and sold to anyone willing to pay for them.

NEVER FILE A PERMANENT CHANGE OF ADDRESS FORM WITH THE POST OFFICE Each year the U.S. Postal Service (USPS) rents out the names and addresses of 40 million Americans (for about 5 cents each) culled from permanent change of address forms. It's better to inform companies of your move individually. Or fill out the form for a temporary change of address. The USPS does not sell lists of temporary addresses, and your mail will be diverted for up to a year.

BE WARY OF WARRANTY CARDS You don't have to fill out the card to activate a product's warranty, but sure as Sunday, these sneaky info snaggers will get your name on more lists than you can imagine. Ignoring them means you won't be notified of product recalls. For items with a safety concern, like household appliances or baby toys, fill out your name, address, and the product's serial number, but skip the hobbies and interests section. As an added measure, write "Do not rent or sell my name" at the top of the card.