WD40 is the worst thing you can put on a bow. I won't even let that stuff stay in the same room as my bows, guns or fishin' reels.[X(]

The canned air thing works, but a blower nozzle with an air compressor is better. TriFlon for the axles and bushings/bearings, a drop of thin machine oil on each screw head to keep them from rusting and a good wipe down with a silicone soaked rag. Don't stick the bow back in it's case until you've let it air out for a day or so to let any trapped moisture evaporate.

Bubba is a wise man. Good advice on taking the bow down and giving it a thorough cleaning and lube job after the season's over.