I attempted to clean my projector with compressed air. I stupidly sprayed the compressed air in the projector while it was running. Since that time, the screen is very dim. I tried another bulb and it worked the same. I cleaned the mirror by the bulb and no results. I am afraid that there is residue on the back of the lense. When the compressed air was sprayed in, a flame came out. What do I do to get that residue off?