yea, it is kinda nasty. Most of those pics were taken when i was taking the metal pan out to clean. But you can see in the middle pic that i have four corner litter pans in there with shavings. - They used them for a long time. It was just one girl that decided she no longer wanted to one day, and started peeing directly on the metal pan. I try to clean it up as soon as i see it, but they primarily do it at night when im asleep. So it can sit there a bit until i wake up. I assume its the acidity in the urine that has eaten away at the tray over the years. - I might add that in those pics, the urine is all cleaned up. What you see is the tray that has been eaten up/rusted out type of thing.
I have wanted to try fleece linings in conjunction with the litter pans, but i could never afford enough of them. It would probably be a futile endeavor tho, they like to chew up fleece items. Ive had to remove half the fleece from there cage.