If they are cleaned up, you could try selling them on ebay. There are a lot of stampers out there who buy unmounted stamps but want to mount them. Or, if that's too much trouble, just offer them on the SCS buy/sell/trade forum for the cost of shipping them. A school might like them to do craft projects with (like painting them and adding letters that they can use to form words). Or, if you have a fireplace, you can use them for kindling. Or give them to your kids for building blocks. But what a waste to just throw them in the trash.