Congress has passed a law that tightens rules on individuals who want to claim tax deductions for donations of clothing, cars and other goods to charity, NBC News reported Jan. 10.

The Pension Protection Act passed by Congress in 2006, which will apply to 2007 tax returns, requires itemizers to provide detailed documentation of giving and obtain receipts from nonprofits, rather than estimating the value of the gifts. For items worth more than $500, taxpayers must obtain an official appraisal to get a tax deduction.

Those who donate big-ticket items like cars, boats and planes can no longer deduct "fair market value," but rather the actual amount the charity receives for the sale of the item.

Monetary donations under $250 now also must be substantiated with a receipt, check copy, or other proof.