DMF 

1970 (?) Schwinn Varsity. Decals - white/cream on blue paint - are nearly intact, but pretty dirty. What can I use to clean them that won't damage them?

The one on the seat tube looks almost like a paper label, but feels like a decal. The script on the down tube I cleaned the end where there is some some paint damage with Simple Green and it seemed to clean up pretty well. But I don't want to use anything that will cause long-term deterioration.

USAZorro

Goo Gone with a non-abraisive cloth or sponge has worked reasonably well for me. I imagine Simple Green could work well without damaging the decal if you don't let it soak for too long. I'm not sure if repeated use over time would contribute to making the decal more brittle, but it is something to think about. Perhaps someone else has more definitive information.

Rabid Koala

I used Blue Coral clear coat polishing compound, a very mild abrasive on mine with good results. Of course, I was very careful and scrubbed lightly!

unworthy1

A friend who does restoration/conservation work on antiques and artwork has told me the method he follows when dealing with an "unknown": start with plain distilled water on a cotton swab, then spit, then water with a special liquid soap the experts use called Vipurex (I might substitute Murphy's Oil Soap). Only after that fails does he try solvents or abrasives, and it's always the least volatile and mildest abrasives first. Just sharing...

Sprint75

Try washing with a mild detergent and sponge. If that's not enough, I've had good results with turtle wax polishing compound.

King of Kadence

On my Schwinns I've been getting great results with rubbing compound.

DMF 

That sounds like very good advice. Thanks!