From time to time I'll cull old flies out of my fly boxes. If they have decent hooks, I'll put 'em in clear boxes labeled "trash - saltwater" or "trash-trout, bass" etc. Like Jay, I'll recycle 'em if I need hooks or, more often, I'll donate them to non-tying friends. Sometimes I'll take these trash boxes with me on fishing trips and if the flies are decent size or otherwise visible I'll imbed the hooks in a stump or fence post near a parking lot frequented by fishermen.