As a property owner I have seen just about anything as well as everything when cleaning out arenas once a renter has vacated.
I have had to replace flooring harmd by pets, redone plumbing that was restrained or harmd by irresponsible people, as well as even had to pay for industrial cleaning in some cases.
This last issue almost had me giving up on they whole process entirely. Sure, I was able to keep the security deposit, but, that didn’t come close to covering the cost involved in repairing the Heating as well as A/C system. Not only did I have to have the ductwork cleaned due to the stash of drugs my friend and I found tucked in the vents, I had to have the unit repaired because they had kept it running non stop with a humidifier set up to help grow the plants in the basement. They had blocked off more than 2 of the air vents with cardboard so that the heat could be directed to the growing section more easily. This had causes a build up of debris at the opening of the vents that can only be described as gross. I had to make sure that the Heating as well as A/C system was scrub as well as safe before I could rent the unit to anyone else. I have changed my rental agreement to include annnual inspections because I want to ensure that renters are not damaging my proberty like that again in the future. I feel it solves the mystery as to why the previous people never complained about anything or asked me to maintenance anything. They didn’t want me to see what was easily going on in the apartment. I won’t make that mistake again.