I have an issue with mudders too! We're not talking dirty cars here, but 4-wheelers that wash off enough mud to fill a 5-gallon bucket! When my car wash was built in 1982, they only put in 4" drains. The bay floors are made with aggregate cement NOT smooth concrete. The mud settles between all the rocks and is time-consuming to clean up. It takes several passes to clean up. We start with a push-broom to sweep up the mud, shovel it, then spray it, and repeat again. Although there is a slotted mud basket under the grate, some mud gets into the 4" drain. So, I'm literally on my hands and knees, using a slotted spoon to scoop mud out of the drain. Often, we have to use a balloon hose to clear the mud in the pipe. Not pretty or glamorous! Last year I raised my wash prices from $2 / 3.5 minutes TO $3 / 5 minutes and created this fancy sign... There's a sign in each bay - posted over the coinbox meter. I'm often on-site and can point to the sign and ask innocently, "did you happen to notice this sign?" I tell them to go to the cheaper car wash down the street, who can better handle the mud (they welcome the business). I'm a Car Wash - NOT a MUDDY Truck wash! I also have 31 video cameras, and live within 5 minutes of my car wash! Fortunately, I have noticed less muddy vehicles coming to my car wash, and more expensive, luxury cars - who appreciate the cleaner bays. Signage and consistency are important.