Nah - I was talking about using a pot on a gas stove that had previously been used on many campfires. The Esbit-type tabs can leave that crud, especially in cold weather, but I carry my kettle in a cotton sack anyway - soot from campfires was the original reason for sewing up the bag.<br><br>Esbit stoves are in all of our day packs and they work fine for us, but they are back-up (emergency gear).