eBay is excellent for testing out the market for things. Check completed listings to see what the parameters are. Sell what makes sense.
As for donating to charity: spending the money locally should make even the liberals happy. It has the added benefit of contributing to a successful business that can then continue to serve and employ others for years to come.
I don't suppose your fence needs whitewashing? Even if it were painted for free, you'd still need to buy the whitewash and brushes. If I were the neighbors, I'd appreciate that, too.
What do you think? http://consequeries.com/