IRS forms and publications
Form 8283 - Noncash Contributions. Attach to tax return if you claimed a total deduction of over $500 for all contributed property
Receipts
When you make a donation of goods, you may receive a receipt listing the items donated. You are responsible for estimating their value. The following valuation guide may be helpful. A rule of thumb is that most used items are worth far less than one thinks unless they are genuine antiques or furniture of solid wood.