There is a toilet bowl cleaner that cost a 1.00 a bottle, it comes out blue, it will remove rust and paint from steel, just don't use it on other metals, it will eat aluminum, and brass, and copper, it will also stain stainless steel.
Good luck on trying to threading that bolt if it's grade 8, i ruined two dies trying to tread one, I went to Tractor Supply and got the right length that I needed, and they where pretty cheap on the price too, you buy by the pound.
Robert
posted using a something and something else.