Just like every other fixture in the bathroom, the janitor cleans her with a hose. If she gets too filthy employees will request he clean her mid-day, and not wanting to deal with this he trains her to clean herself and/or the bathroom a bit between surges of "customers." Since he has her all to himself at night and makes extensive use of her, he also makes her stay in shape - sit-ups, push-ups, jumping jacks, etc.

At first she didn't want to work out for a few hours every night after a long day of being abused, but after the janitor shoved a toilet brush up her pussy and tried to twist her nipples off she got the message.