Drill a small hole between the o and u on the bottom of the mag. Just go through the first layer of plastic. Then shove a screwdriver/nail through the hole you made, depress button and release floor plate by sliding forward. Havent needed to clean mine yet as i just got it but i've read thats how its done.
As far as the mag fitting, i had to file the top half inch of plastic at back of the clip(in front of bolt along the magazine slide )untill it was almost gone. It was preventing the bolt catch from operating. I suppose i could have filed the bill down a bit but that woud be more work and removes the magazine further away from the magazine release latch.
