We usually rent a Big Green Machine with upholstery atachments and pick up ZEP Commercial Carpet Cleaner at Home Depot. Also use ZEP Carpet spot remover prior to the carpet cleaning on those tough spots We get in the corners and hard to get spaces with the upholstery attachment and get the big areas with the machine. We then use it on the truck and any other vehicle upholstrey as well as the sticks and brick if we are there. One Day rental is 40 bucks and a gallon of Zep is 9 bucks which last forever! Spot remover about 8 bucks for a gallon and again last a long time. Been doing this for years from our Class A to TT now the 5er. It smells fresh and clean and the Big Green Machine is strong enough to pull out most sand and other garbage in the carpet. We had a small dog for years and it worked well.