This is my No 2 Box Brownie Model F.
Takes 120 film (on old spools).
I removed the face plate and lightly cleaned the lens and the viewfinders. The viewfinders were so dirty inside it was impossible to see anything through them so I had to try and clean them.
It’s pretty simple to prise the front plate off. There’s a sort of pinch mark half way down each side of the plate and I used a thin flat head screwdriver to just ease it off. After cleaning it popped back on securely by itself.
This model has “stop openings”. The central slide above the lens has 3 openings. According to the manual the largest (when it is all the way down) is for snapshots and ordinary pictures.
The middle stop is for bright light conditions and the smallest stop (slide all the way out) is for timed exposures on cloudy days. See the manual here.
I should have read the manual before I took my first film!