Breeding in a growroom?

I want to pick back up where i left off about 10 years ago breeding. My growroom is divided into 2 sections, 1 for veg and 1 for flowering. There is A closet in the room that I want to use to grow the males out in but im short on ideas for how to keep the pollen from getting out into the main room. I would take pictures but I use lenox and cant figure out how to get my cameras memory card to read.

Thanks for any help!