Not sure here I learned this but I will tell you it works wonderfully well, especially if you have kids. Go out and get a few small sturdy boxes or even milk crates (better yet) if available. Make a rule that everything transported, or used or finished within the car (trash included) gets put in one of the storage bins. Make another rule that whenever anyone leaves the car they have to bring the bins into the house and do something with the contents. Try it and see if it helps to keep the inside of your car cleaner.
Does this sound like your house? As soon as people enter your home the drop everything right by the door, remove their shoes, coats and whatever else they have. Before long this area is a cluttered mess. The solution is to a shoe storage rack. This clever storage piece of furniture is perfect for shoes especially. There are many different versions available. Some are just racks, others are designed like a bench and still others are designed as an attractive container that stores more than just shoes.