Obviously you aren't going to hose down your carpet mats to clean them. Nothing is more uncomfortable than driving with wet ankles. Just run a vacuum cleaner over them after they start getting dirty. (Like the second hour you use them, and every day thereafter.) Here's a tip: If you can't get your Hoover upright in there, take the mats out first. Vacuum them on a flat surface, and then put them back. In a hurry? Shake them out, baby, and they'll be good to go. Another tip: When you shampoo your home's carpets, do your car's as well.