Originally Posted by
flguy
its for a great cause
Indeed it is. I noticed this part in the T&Cs for the Susan G Comen one "For charitable deduction purposes, each mile is valued at 2.75 cents per mile if fewer than 6,000 miles are awarded and 2.5 cents per mile if 6,000 or more miles are awarded."
I'm guessing they will say your deductible amount is your donation less their valuation of the miles. Though in reality, you can probably just screen shot the donation or the CC statement as proof in the event you're ever asked to provide support for your charitable donation deduction.