Whats the best way to clean the neopreme seat covers?

What are you trying to clean off of them? I think there is an old thread around here about dog vomit...
Spot clean with a damp cloth and a mild solution of fabric cleaner. Hose would work too but I think I would try the damp cloth first...

After a Salmon run fishing trip, my covers were a disgrace. I took them off, threw them in the clothes washing machine then into the dryer on low heat. Like new, no problems whatsoever. Thomas

I did the same as Canope, works like a charm, just use cold water and either air dry or low low temp on the dryer!