Quote Originally Posted by pat mccarthy View Post
i know a guy whats used molasses its about the same as the stuff i use called evap a rust . it just a verry mild acid from mother nature and is not toxic .if pitts are under the rust there going to be pits . any mild acid will work SODA POP . i would watch any acid hotter then this stuff were etching could occur
Very good info . I was also going to suggest soda pop. I also remember reading that you could dissolve rust in a tank of water with a battery charger and electrodes inserted into the water. Something like this, be careful with this. I also dont know if the process will give some kind of weird charge to the block that could interfere with electronics later on. just a idea.
YouTube - ‪Geoff's Science Garage - Electrolytic Rust Removal‬‏


Another idea is naval jelly and wrap the block in a trash bag for a bit.
But like Pat said , if theres rust there is pits. After the rust removal you will still have the pits.