What causes cigars to burn with a black charcoal-like ash?

A: This “black tobacco ash” you describe, if it’s hard like charcoal, then it may possibly be a ligero leaf that ended up too close to the binder, or the binder cracked when rolled exposing the ligero behind it. If so, I have experienced this, too. Ligero burns very slowly because it is so oily, which is why it will char-up when you continue to relight it. You might want to let the cigar go out and clip the embered ash, etc. up to the base of the foot and re-light again. In some cases, the cigar will burn past the charred ember section and straighten itself out. If not, you’re probably doing the right thing by tossing it, but I hate chucking away a good cigar.