A build up of shit and toilet paper bits on the back of the seat,
when you wipe your ass with cheap toilet paper.
Man, at work there's always toilet dander on the back of the seat, because my boss buys the cheapest fucking toilet paper.
When you use a public restroom and its so nasty you squat over the tank and drop a shit in it.
Man that gas station toilet was as so fucking nasty I had to drop a poop-pedo.