Canvas bags stored below in lockers on our boat have to be treated every so often with a good vinegar wipe down or mold creeps in. Zippers MUST be treated as well or they will completely freeze up. I used Bees Knees zipper wax on bags in storage. For you surfers, I think sex wax would work as well but I am not 100% sure. On our dodger, bimini enclosure, I use Zipper Lube with the exception of the front zipper. It is prone to leaks so I use the Bees Knees generously and it helps to seal up the zipper. Bees Knees also works to keep our companionway hatch sliding easily.