Go to local auctions, many times the stuff that doesn’t sell goes on a pile and the pile gets auctioned off at the end (usually 1 or 2 dollars). Pay attention to what others buy, usually people only want a specific item in the box of stuff they got. Ask them for the rest of it. Speak to the owner, there may be things thought not good enough for the auction, or let him know ahead of time you will pick up anything left over and give most or all of it to charity.