Tips on cleaning carpets, floor mats, and interior plastic trim on your car at home. The process is cheap, easy and effective. Heres how to clean your cars interior at home. STEP-BY-STEP GUIDE: \rbr\rbrCleaning an entire cars carpets should only take a few hours hours, depending on the size of the vehicle.\rbr\rbrOn thiswere cleaning up the interior of our Project Rodeo 2003 Isuzu Rodeo. The interior of the Rodeo, especially the trunk, was stained with nearly 12 years worth of mud and dirt. And with no floor mats, the dirt was ground directly into the carpeted floor of the vehicle.