Got a clunker to unload? Sometimes a charity is better choice

— -- In the past, if you owned an old car that mortified your children and leaked more oil than the Exxon Valdez, you had two choices: sell it or donate it to charity. Now, the government's "cash-for-clunkers" program has added a third option that has generated a lot of traffic in car dealers' showrooms.

The federal Car Allowance Rebate System (CARS) program gives car buyers who trade in their gas guzzlers a rebate of up to $4,500 toward the purchase of a new, fuel-efficient vehicle. The program is designed to stimulate car sales and get environmentally unfriendly cars off the road. Dealers are required to disable the engines of the used cars.

The program has been wildly successful, which means a lot of used cars that might have been donated to charity have met a grisly junkyard death. Some charities say they've seen a decrease in the number of donated cars since the program was launched last month. That's not surprising, because the average tax deduction for most donated cars is about $500. If you're in the 25% tax bracket, that works out to a tax savings of $125, which won't even cover insurance on a new set of wheels.

Still, you shouldn't automatically assume that CARS is the best way to dispose of your clunker, says Bill Visnic, automotive expert for consumer website Edmunds.com. Things to consider before you drive your beater to the dealer showroom instead of a local charity:

•Whether your vehicle meets the criteria for the program.

Even if your car hasn't had that new car smell since 1989, it may not qualify for the program because it doesn't meet the government's criteria. To qualify for CARS, your vehicle must have an EPA city-highway combined rating of 18 miles per gallon or lower. In addition, the vehicle must be drivable, have been manufactured in model year 1984 or later, and must have been continuously insured by and registered to the same owner at least a year before trade-in.

Some real clunkers will miss the cut because their combined mileage rating exceeds the cutoff, Visnic says. Some charities believe the CARS program will increase donations, because consumers will donate cars that don't qualify for the program.