I have a small 2'x2' closet with a door, I put a cat door and dedicated to host the litter box for a few years now.

I recently changed my mind about the whole thing because how much space I am wasting, and decided to build another box, (e.g I want to reclaim the space for storing human stuff!) However, the inside smells aweful and very dusty.

I plan to seal the floor, drywall and everything with primer again. after through cleaning first. The floor is plywood subfloor and I am not sure any waste was soaked in there, it just smells bad.

Would just bleach and nature's miracle get everything sanitized again? Also have a steam cleaner ready at my disposal.

I know it sounds quite bad.. any cleaning tips or primer/sealer recommendation is appreciated.