For those bikes, to improve the rough to the hand feel and attempt to do no harm my process is :
Art brush , and small jar ( olive jar or baby food) of PB blaster penatriong oil ….
Brush the oil or eye dropper on the rust spots , ( wipe away excess the runs on unaffected areas / avoid stripes or decals ) leave overnight
Come back in a day or so with :
-Q tips ( not the plastic stem / the breakable cardboard stem type) break them in half : use the cotton end and the stem end to lift and remove rust grit
- Wooden coffee stirrers broken in half so the break is spiltered, same thing : pick at , saw action to gently lift loosened rust particals
- in my kit for this is also dental pics and a blue crab pick for areas where their is clearly no paint just a bare spot
Use q tip stem end and cotton side to lift away and wipe dissolved rust bits
clean the areas you worked on , dry then reapply penetrating oil and repeat ….
the rough gritty to the touch feel will improve , and the rust patches will be smaller less visible ….. but you will not eliminate them
You can repeat several times , or until you’ve cured yourself of the urge to “fix that “ and you have no desire left to mess with it every time you walk by the bike ….
Once you are satisfied that you’ve improved things , now just wax the bike , first with a super mild polishing wax and a mini harbor freight cloth wheel / at low speed , then with regular car wax , by hand leaving liberal amount of wax, by only light pressure on the cloth.
Now you’ve got it out of your system and the bike will look vastly better ….. just back up about 5 feet when you want to admire it
and the rust in paint won’t bother you.
That’s how I get over the urge to be too aggressive with that kind of rust on paint mix , and it truly does look better and tubes feel smoother to the hand.