one of my favorite joke :
Son: Mom, when I was on the bus with Dad this morning, he told me to give up my seat to a lady.
Mom: Well, you have done the right thing.
Son: But mum, I was sitting on daddy's lap.
WD-40 works pretty good, just soak the grease with it and scrub it off with a wire brush/rags. A cheaper version is just kerosene. Gasoline works good also but then you have to worry about blowing yourself up so I don't recommend that. The lead screws can be cleaned with a piece of string/rope...