Would it really affect the performance of the seat, if I tossed it in the wash? Handwash cycle, maybe?
FWIW, I tried pet mess cleaner-- that enzyme stuff? That just made the van smell like pee AND the cleaner, which was worse.
I went to a presentation by a child seat safety specialist, who said that machine washing takes off the flame retardant chemical. My guess is that is the reason.
I have and would wash on the gentle cycle and air dry.
I highly recommend a piddlepad to prevent potty leaks. It has saved us quite a few times and is machine washable. I just had to wash it for such an occasion last week. I recommend the deluxe versus the basic one. It seem to offer more coverage. I bought mine through amazon, but BabiesRUs has it too (link below).
We have a Radian and I washed the cover and it was very difficult to get it back on. Sunshine Kids did not do a good job in this department in making it easy on parents. What were they thinking?
I wash mine on the handwash cycle, with just tiny bit of natural laundry soap. Cold water.
Don't put it in the dryer though!