Char buildup in the hot melt application pot can cause serious problems. Char occurs when excessive heat raises the temperature of an organic material such as a hot melt. This heat causes the polymer to break down into small chain lengths, and eventually into carbon. The carbon material sticks to the side of the pot, and eventually breaks off in visible chunks, which we refer to as "char buildup." In the early stages of char buildup, the hot melt darkens. This is due to the dispersal of the carbon throughout the molten material. All hot melts will form char eventually, but the use of antioxidants will prolong the life of the product. Once this char has built upon the sides and bottom of the pots, the flow of the hot melt breaks off the char. HOW TO AVOID CHAR BUILDUP? THE REAL ANSWER IS TO MAINTAIN AND CLEAN YOUR HOT MELT POT ON A REGULAR BASIS, AND TO WORK WITH A HOT MELT THAT HAS SUPERIOR HEAT STABILITY.