We have a Neighborhood House in my town. Anything you don't need, you can pack in a box and drop it off at the Neighborhood House. Volunteers go through it and organize it. Sometimes, you can see people walk up to the porch and collect stuff that's been left. It's much easier to let go of stuff when you see that. Sometimes I give away stuff now that I might have use for because I know it's better to see someone walk off with my almost new pair of shoes than to have that pair sit in a closet.

Neighborhood House is one of the best antidotes to hoarding:)