Yeah, I have thumb callus too.. I used to snuff out my bowls with much finger too, but because of what I do, My hands must be clean. I have a silver poker for scraping and scrambling my bowl too.. but ya know when you take the first hit off a bowl and tthe weed raises.. yeah, thats when I use my lighter. also, My finger wont go into the one hitter I use for my exotics, so i gotta use the lighter. I've never had any melt or explode..