rust stuck

I'm new to this rust world but here it goes i have a 1939 3 speed gear box and the shifter is rusted stuck how is the best way to get it working again. Also i would like to learn the right way to z a frame on a 1930 ford sedan front and back thanks.

 

I got a 39 box that had been in a field for decades. The whole thing was fuzzy rust. I did the molassas deal and it all freed up. Shifter shifted and gears moved. I was pleased. I used 3 parts water and one molassas. Took a while and got a terrible bunch of floating stuff on top.

 

Wheres your intro?? You will get a bit more response.

Dawg