Product Care - Glass
The way you care for the glass covering your framed art may depend on what type of glazing was used. The piece shown here has three types of glass on it, showing you the differences in reflectivity. What you can't see is the difference in UV filtering to protect the art. The "Museum Glass" shown in the middle looks nearly invisible and protects the art, too.
Your framer can provide specific directions for appropriate cleaner or cloths. In general, simply leave the framed piece alone with the exception of periodic cleaning. Feather dusting helps remove dust particles that may land on the glass. You can also use a soft lint-free cloth or newsprint and glass cleaner. Never spray the cleaner on the glass. Instead spray onto the rag and then wipe the glass.
Closely inspect the glass on a regualr basis to see if it appears clear on the inside too. Various chemicals in dyes and inks used to make prints and mats can potentially off-gas. This may result in a cloudy residue on the inside of the glass. You can take the piece to your local framer to have it opened up, cleaned and placed pack in the frame.