They are recommending to use ISO which I find interesting after the comment from @Abysmal Vapor.DotLeaf_Alex (Reddit AMA)
Score hidden·26 minutes ago
during our long initial testing process, we only had 1-2 tanks fail so we expect a fairly good lifespan out of the chambers as long as you keep them cleaned periodically. I always recommend cleaning with isopropyl alcohol and you should be able to wash them out with that as well without damage.
I guess we shall see!Carbon Black (if Black)