Here's a fun idea to help you part with some of your excess stuff:
a good old-fashioned swap.
The general idea is that you get together with a bunch of friends and/or neighbors and everyone brings things they don't want anymore but that are in good, usable condition. Then you all go "shopping" for each other's stuff!.
You can host your own — make it a party! — or sign up for the August 18th event at East Providence's wonderful Fuller Creative Learning Center.
If you decide to host a swap party, you can do it indoors or out, setting up tables or picnic blankets to display the wares.
It can be a pure swap ("I'll give you this coat for two of your books.") or you can assign items a value or rating. Give each item a star rating and trade based on how many stars items "cost." For example, you could trade three one-star items for one 3-star piece.
Your goal should be to end up going home with less than you brought, so choose to swap for smaller items or swap multiple items for one of something else.
At the end of the swap, offer to load up your car and drive ALL the leftovers to a donation center. Bring items to the closest one (Search for "donation center near me.") or your favorite charity.
Whatever you do, don't let that stuff back into your house! If you already decided you were ready to part with it, trust your instincts and stick with your decision.