Hi Erik,
With the V4 Miniscopes, once assembled you should seal around the image sensor PCB with some 5-minute epoxy or optical glue (never use cyanoacrylate glue). This should stop any dirt dust from ever getting to the image sensor or emission filter. Also make sure everything is screwed on tight and there are no gaps between housing parts.
If you do have to clean things, look up some youtube videos on cleaning optics or cleaning the sensor of a DSLR camera. The only place to be very careful cleaning is with the coated surface of the filters.