I filled the doors with 'great stuff' brand expandable foam (4 cans per door)..... i did this because even when the doors get beat hard they will hold the shape and always close..... and it made for a nice semi-soft arm rest......the koozy is just chillin there.... its a coffee can that the cup holder is made from........i chose canvas because leather or vynal gets really hot, but you are right, it will probably get wet and dirty