I would definitely ask your yard before you start filling all your scrap appliances with it. Any metal dust is a highly undesirable item for yards. Its caustic to breath and must be slowly salted in with loads going to the mill.

About 2 weeks ago I had a guy bring in a half full 5 gallon bucket of lead dust from a shooting range intake. He brought it in open and someone left it in my office. You can bet that I immediately called him to come get it.