What did you try? Have you tested any solvents for color fastness on hidden parts of the body?
I'm curious because I have a Royal with paint drips on it but obviously anything that removes the bad paint is likely to remove the good.  But ink might come off with something less than a paint stripper. 

@overwood: I used dishwashing soap, all purpose cleaner, TurtleWax, denatured alcohol (96%). The latter dissolved the paint almost immediately while having no effect on the ink. With Scotch Brite it was not possible to sand away the ink. I tried until I reached the metal of the body. I am under the impression the ink has fused with the paint.

@Pete: thanks, good to know there is something on the market for this, I will check if I can find it here.

@overwood: about the paint drips on your Royal, if it has a glossy black finish, it might be possible to scratch them away with a finger nail or a paint stirring stick. I had a 1938 Erika S with a lot of small paint splatters  (0.5-1.5 mm) and I managed to remove them all with the above mentioned method.

I just noticed some inky fingerprints on my SM9, which is also a smooth creamy finish. Without thinking I grabbed the 70% ethanol I had sitting there for something else and started rubbing some with a paper towel. The ink came off with some effort but it did not harm the paint. However this was probably ink that I got on there only a couple weeks ago.