A can of compressed air does wonders; just be sure to spray with enough distance not to damage your art. And you definitely want to avoid using paper towels on your artwork because they can be abrasive. Stick to lint-free cloth (an eyeglass cleaning cloth does the trick) when the need arises, and if you're really of the careful sort, wear clean cotton gloves when handling/moving your art while cleaning (your fingertips leave an oily residue that can damage art surfaces). More great tips here about caring and handling artwork here.
You can get plastic cleaner at a shop on pico near sawtelle in west la. They sell custom plexiglass and a big bottle is about 16 dollars. It should last a long time. It is what was reccommended to me by the high end art framers I used, for two art pieces. Also use windex without ammonia on glass frames if you have to use windex, the classic kind will discolor the glass over time. You should also spring for the uva blocking or museum glass/plastic if the art will be anywhere near the sun. Hope this is helpful.