I'm guessing he started out as a boat detailer.
If done right, a pressure washer would be OK. Just don't get too close to the surface, keep it the pressure on the low scale. I also believe I would not do it right and a few patches would be the result so soft car wash brush here.
I could see it working on car seats as well long as they are just surface washed. The trick is to not let it soak in, same as a carpet shampooer.
2011 PrimeTime Tracer 2600rls
2001 GMC Yukon XL 2500, 6.0L 4.10:1 axle ratio
Nights camping 2014 - 17
2013 - 15