The best solution to getting out of your wetsuit without getting it filthy and then drawstring the mat into a bag, to keep it all dry in the car or van. You still have to wipe the bottom of the mat / bag off though :) .  ION Say.. 

You know the feeling after a good session, man, sand everywhere! Plus, often there's no soft, clean place to change other than the car park.  With ION’s CHANGING MAT / WETBAG you can easily get changed anywhere without damaging or getting your wetsuit dirty. Even better, the easy closure system ensures you can stash your wet stuff in the bag and carry it around without making any mess—brilliant!