Dust parcticles in the screen

I have Neopix Prime NPX540 more than half year and I have a big problem with dust particles in the screen (mostly viewable on black screen, like “star wars”, and in the right upper corner on white screen). When I purchased the projector, there was almost no dust in the screen, and after a few weeks the dust particles started to show up. Now, after half year the dust is so dense, that on the black screen it reminds me the night sky. The projector is in bedroom, no dust environment, air purifier in the room. HOW CAN I CLEAN IT? Under the sticker on the bottom there is no gap to clean the projection glass.
I use the projector every night and I don’t want to send it to the service.
I have had Apeman LC550 projector and the dust particles and unability to clean it was the same problem.