What to do about rust on frame?

I've got some bits of rust on the frame, and I want to prevent it from getting worse.
Should I just put some grease on those spots or something?
Any advice is appreciated!

 

I'd wire wheel it off and degrease it then coat it in a rust converter like POR15 or something. I'd also spray something like Eastwood internal frame protectant or a comparable product inside the boxed portions of the frame while I was at it. The boxed part of the frame is what rusts out without you being able to see it. The surface stuff is just icing on the cake.

There is a mega rust prevention/protection thread on here somewhere with millions of links to other rust threads. I'll see if I can find it.

EDIT:
https://www.tacomaworld.com/threads/rust-prevention-treatment-consolidation-thread.355928/