Rob you might want to try bar keeper friend!
I also have a 80's Comp thats in bad shape; the chrome forks are rust pitted to the metal. I made a paste with the BKF and let it sit on the rust for about 5 mins then steel wooled the chrome total rust came 98% off will have to treat the whole frame once I get some more wool!
It made a BIG difference on the rest of the frame!