I used "Camp Dry" waterproofing spray from Wal-Marts to waterproof my interior cloth. It took a full day and a half to dry, but I tested it out by pouring some water on it, and the seats seem to be pretty waterproof. Definitely enough to resist some light rain, mud, or spills.

I'll keep you posted on the long-term effects.

I wanted to get waterproofing without dealing with sweaty neoprene or expensive waxed canvas seat covers. So far, so good.

This mod cost a total of $4.00. I put one coat on. I'm going to run over next weekend with another coat just in case.

BTW, I have the canvas/cloth - not the vinyl seats (or "leather-appointed as Jeep calls them).