I've used them in the nastiest of conditions. You can pull it out to a large enough area to catch a spark, you can shake water off of it, you can use the vaseline itself just like... er.. vaseline! I have found NO objections to this tinder!

Try this: 1) melt the vaseline in the jar, in a microwave, until just liquid. Then dip the cotton (real cotton.. not synthetic) into the liquid. Lightly..
2) to store, I push them down a McDonald's drink straw (large bore) with a toothpick. Cram them in, flame and HEAT (carefully) and pinch closed with pliars each end of the straw. They're any size I want them to be. Fit in any kit I've carried. And both the cotton and the straw burn well!