(MONEY Magazine) – If the bottom line on your 1991 tax return makes you wince, here's an offbeat write-off to consider for '92 or beyond: the next time you're ready to sell your car, donate it to charity instead. As long as you itemize on your tax return, you can claim the car's fair market value as a write-off on your 1040. The charity, of course, wins too. It will either auction the car and pocket the proceeds or put the auto to its own use. And, oh, yes: most charities that accept sedans and wagons also take recreational vehicles and even boats. What's more, smart auto buyers can often snag a used car at a charity's auction for 10% to 50% below what dealers charge. At least six national charities including Goodwill Industries of America, the National Kidney Foundation and the Salvation Army run vehicle-donation programs, usually through local chapters in major cities. For example, donors to the Davis Memorial Goodwill in Washington, D.C. turned over 2,310 vehicles last year, up 21% since 1989. This month, the charity will hold its first boat and RV auction, and in June it will sell 25 classic cars, including a '64 Stingray valued at $22,500. If you're intrigued by the notion of donating a car and have a favorite local charity, call the group to see whether it accepts used autos. Be sure the amount you'll claim on your return is realistic though. Most libraries stock used-car price guides, such as the National Automobile Dealers Association's Official Used Car Guide, to help you determine the right prices. Bear in mind, though, that the prices listed are for cars in good condition. And if your car is worth more than $5,000, the Internal Revenue Service requires a written appraisal. One last thing: don't forget to collect a receipt from the charity.