Anything crashed is not worth being used. In fact I try to make sure they can't be used by cutting the frames in half. Every so often we load up scrap metal and take it to the scrap yard. I work at a bike shop so all of the damaged wheels that get replaced I take them. If the hub is half way decent and still usable even for parts I often cut out the spokes and save the hubs just recycling the spokes and bent rims. Occasional we get a bike or two given to us. If it isn't worth the effort to fix or is too far gone I might try and salvage a few parts and then off to the scrap yard it goes.