Here’s a tip from the I-R-S. . .   

Americans are very generous.  But remember.  Even if you itemize on your tax return, you won't be able to deduct your donations if you don't have the right paperwork.  So make sure for donations big and small, you get a receipt or record-of-giving.  Cancelled checks and credit card statements are good too. And if you donate clothes or items from around the house, they must be in good condition.  Finally, your donation must go to a qualified charity or house of worship to be deductible. And don't forget that receipt! 

Learn more about the rules at I-R-S dot gov.