The next time you spot a classified advertisement that promotes a sure-fire, get-rich-quick scheme or a miracle diet, you had better beware. The ads might be phony, planted by the U.S. Postal Service as part of a campaign to alert consumers to mail-order rip-offs.

The advertisements are patterned after ads that were used by companies convicted of mail fraud, explains Kacy McClelland, a consumer protection specialist in Pittsburgh, who thought of the bogus ad project and got $500 budgeted for it. McClelland wrote 57 newspapers in western Pennsylvania, West Virginia and New York last week, explaining the program and asking if an ad could be placed in last Sunday's edition. Ten newspapers agreed, 10 said no, and the rest didn't respond.

"The purpose isn't to call someone a dummy," McClelland explained. "We just wanted to see what kind of market these ads had and we wanted to tell consumers to be careful."

One phony ad offers readers $750 a month for stuffing envelopes at home. Another ad promotes a "European Reducing Formula" that promises consumers they will "lose weight like never before."

If someone responds to the phony ad, the postal service returns their postage with a brochure that warns them about schemes that involve envelope-stuffing, medical fraud and chain letters. McClelland said 25 persons have responded to the ads so far.

Postal investigators estimated mail-order hucksters bilked $500 million from consumers last year.