I give a little money to a few charities every year and it bugs me that they spend some of that money sending me mail asking for more money, which I ignore out of a matter of principal. I am not the only one who thinks like this, so it seems like there is a business opportunity here for someone. If you could set yourself up as a transfer point for charitable donations, people could make their donations to you, you could give them a receipt, skim one or two percent off the top, and forward the rest to the charitable organization, you would be doing everyone involved a big favor. It would keep the charitable organization from wasting money on mailings to people who do not want them, and it would keep the people who are donating money from being hounded by repeated requests for more money. Getting such a business off the ground would take some ingenuity and some financial backing. If you were taking one percent off the top, and say you needed to gross $100,000 to make this a worthwhile endeavor, you would need to collect ten million in donations. If you were collecting $100 on average from each donor, that would mean you need 100,000 donors. To contact that many people, you would definitely need a big advertising budget, hence the financial backing.
Another approach would be to contact some charity organizations and see if they would be willing to put you on their advertisements. It would be free advertising for you, and you might be able to sell them on the idea that they could get some additional funding from people who would otherwise not be interested in contributing. You would, of course, have to establish some credentials as a legitimate business and not some kind of nefarious confidence man. I imagine bonding might be in order.