You must maintain a bank record, payroll deduction record or written communication from the organization with its name, the date and amount of your contribution.

FORBES: 10 Simple Rules For Tax-Wise Gifts To Charity

To claim a deduction for money you donate, you must maintain a bank record, payroll deduction record or written communication from the organization containing its name, the date and amount of your contribution.

FORBES: Saving Taxes By Giving To Charity

Clearly, any rounding up you do or extra funds that you donate to an organization which is recognized by the IRS as a qualifying charitable organization would result in a charitable deduction (assuming, of course, that you itemize your deductions on a Schedule A).

FORBES: Run With It: Sports, Races and Taxes