Folded mine up according to demo. Great, space-saving idea and they are ready when I need them.
For those worried about moisture - even over the short term, think about adding a desiccant pack or two into the roll. I save all the ones I get with clothes and electronics and put them into my tool boxes. They can even be "re-charged" by baking them at lo temps.
They even sell big, hurky ones at the grocery designed to relieve excess moisture in bathrooms. They work great. My daughter spilled water in her trunk and it started to smell musty after one day even after using the wet vac. Threw one of the biggies in the trunk and it sucked all of the moisture out.
Science is your friend....
Best,
M