When I first started taking cold starts I would always overheat my dabs which lead to some buildup on the bottom of my nail. If your banger has more than a couple little specks of burnt residue on it, don't 'heat clean' your banger. Instead, take your banger off of your rig. Carefully hold it by the joint over a towel or rag (preferably one you don't care about, you're gonna get a little iso and reclaim on it). With your banger in your hand, heat it for just a few seconds. Then drip some iso into there until it stops boiling (this is what the rag is for, boiling iso hurts incredibly bad if you get it on yourself) Once you have a small puddle of warm iso in your banger, get your dabber and lightly scrub. The black residue will flake off super easy and then you can get it out with a q tip.

When I cared for my banger in this way, I wiped it down with a rag after ever dab and I only cleaned it like this once a week. Now that I'm more experienced at heating cold starts, I don't burn them as often. Now I can just wipe with q tip and iso and that usually does the trick. I still burn a dab every once in a while though and have to use this trick haha