My 1958 road bike is almost back up and running and I would like to take it on some long outings. My only worry is the frame. It’s sound, but paint is missing in quite a few places. The reason I’ve not had it resprayed is because of the fantastic transfers, they couldn’t be replaced.
I was thinking of rubbing a greased cloth over the frame?

Framesaver?

Just Googled it, looks good for the inside. Not too sure about the outside?

clear coat of varnish.

A good car wax applied reasonably frequently will stop moisture getting through to the paint and bare patches.

Or wipe it over with Purple Extreme.

I’m thinking you could just wipe it over the outside on the bare metal areas. it dries reasonably solid so will stay put and have less tendency to wipe off or pick up dirt as would grease or similar. That or you could just use clear nail varnish?

Nail varnish on scratches is the classic. Go clear if you don’t want a random colour.