Recently tried this simple fire starter on a climb of Mt. Stuart. You take a handful of cotton balls and smear them really well in petroleum jelly. Toss them in a ziplock. Weighs nothing. Each cotton ball burns for close to 5 minutes. This gives you plenty of time to get your campfire started, which is useful for working in wet environments.  It’s a no-brainer essential that even minimalists can accomodate.