Dealing with surface rust on a raw frame - is white vinegar or coke in spray bottle and aluminium foil sheets the only way to go if I don't want to give it away to get it blasted?
When I wet blasted my frame I was left with a very dusty coating of fine powdery rust. I wanted to use a weak solution of phosphoric acid to clean it off, but couldn’t find any so took a punt and used cola. It worked a treat.
I’m guessing your rusty bits are more pitting in the surface. Try cola, but I think you might have more success with the white vinegar and it’ll need a little soaking if it’s anything more than dusty surface stuff. You could wet a bit of cotton wool with vinegar and stick it on any scabs for a few hours and you should find it’ll dissolve away the rust and leave the clean metal behind.