[malandrew]

Why not simply install elevators with a grated floor and install a plastic tarpaulin at the bottom of the shaft. This way and urine would not stay in the elevators. It probably wouldn't do much for poop, which would still have to be removed manually, but I imagine that simply having the elevator open on top and bottom would allow enough air to circulate to eliminate the smell.

Alternatively, is there a way to detect when poop or piss touches a service and trigger an automatic lockdown of the elevator until an officer has come to inspect it and release it? Once someone has been trapped and fined once, they are more likely to avoid doing anything that triggers them getting caught in the elevator.