Just to let you guy's know,
I replaced my lamp for the first time on Monday,
Something that I always wondered was if the light path was sealed so no dust
could get in the way. This is an advantage so you can use compressed air to blow
out dust from the fan area. I never found out the answer. I took a risk when I changed the lamp.
I blew compressed air into the lamp area with the lamp out. Dust flew out the air intake.
I also blew in the intake and outtake to clear them out. Not so much dust.
I then micro fibre cleaned the prism and lamp housing and reinstalled the new lamp.
I turned the projector on to see if dust went into the light path, they appear as blobs on a white screen.
I put up a white screen from the S&M blu-ray and everything was clean and clear. All good.
So my guess is the light path is sealed from dust and you can use compressed air to clean.