Perhaps some sections of the thread might help.
Wouldn't touch a precious dial - or ANY if you're not a person with fine-motor skills, it's a delicate job. Some watchmakers are able to help, but don't trust in good intention only, any destruction is final... also think about losing the patina. Rather sell a bad candidate and look for a better one.
You can clean newer glossy dials with very smooth and clean microfibre (or the tips I've mentioned in the thread) - just breath on the dial and wipe fingerprints or dust quickly away. Never use cotton swabs, the cotton is too rough and scratches the lacquer. Matte dials: don't touch, except for dabbing (not rubbing) dust with Rodico away.