Depending on make & model
Uninstall projector from bracket (if required) Remove clean and wash all filters. Remove top cover and check for serviceability. Remove lamp housing and check for serviceability. Test the leveling foot if necessary. Remove and test the front focusing knob using a flat blade screwdriver. Remove the inner top cover and prepare the unit for cleaning. Using compressed air, give all internal components an initial blast. Remove all old lube/grease using a cotton bud soaked in alcohol. Remove all sticky caked on varnish using a cotton bud soaked in alcohol. Clean all interior components using various brushes. Slide out the lamp control module exposing the fan assembly. Using a toothbrush, brush the fan blades inside and out to remove dust. Clean the fan through to the interior with compressed air. Using a shop towel place it inside and around the fan housing. Remove the grease cap (EIII model) from the fan. Set aside. Check fitting and refill the grease cap. Apply a small amount of grease to the fan belt. Check power supply to the unit. Locate the rotary contact mechanism and check for a tight fitting connection Clean all projector power contact points with alcohol wipes. Give the power assembly a shot of compressed air. Using a shop towel and glass cleaner wipe down the exterior surfaces. Using compressed air blow the dust off the lens. Wipe and clean the lens surfaces with alcohol wipes. Refit top cover and re-fit to mount (if necessary).