First and most important "DON'T EVER BLOW ANY KIND OF COMPRESSED AIR INTO PROJECTOR !!!!!" as this will most likely push dust into the optics. Disassemble as much as you feel comfortable with and use a vacuum and brush but also caution as a vacuum will generate static. A humid environment will help with most of the static.
"Smart enough to know better, to old to care" ------ Dedicated Bat Cave Home Theater, JVC RS49U/Mitsubishi HC7900DW Projector, 110" 16:9 Jamestown screen with variable power masking for CIW 2.50:1 to 16:9, Marantz 7009 with 7.1.4 Atmos with Ohm mains,3 DIY Subs (2 15" (1 ported, 1 sealed and a 12" 4th order bandpass), 1 DIY butt kicker, Custom Built HTPC, 18TB DroboFS NAS