Besides maintenance on the TB, I cleaned out my apartment's A/C / Heater unit. Disgusting doesn't even come close to how the inside looked, roach carcasses, roach eggs & feces, slight mold, dirt, dust, cobwebs. I used a whole roll of paper towels, sacrificed my toothbrush to scrub, and used 3/4's a bottle of Purple Power to clean it (good thing I keep gallons of it under the sink). Spent 2 hours taking it apart, cleaning the internals, rinse out the filters, and putting it back together. Should of took a before and after, as this thing was clearly not maintained since it's installation like 20yrs ago. I have been putting off using it because it happened to spread mold spores in my apartment when it was on, my girlfriend got sick a lot during that time as well for no reason. Discovered this as I was cleaning and dusting before they re-painted my apartment when I renewed my lease last year. Now we can enjoy the nice A/C without worrying about getting ill.