How to remove stuck clear pipe off flowmax macerator

X2 on the hot water. Pour it over the outer piece so that it _almost_ runs over the actual joint, then twist it off almost immediately (before the heat conducts in to the inner piece).

I think it's 3M that makes a silicone grease that probably would prevent this if you apply a bit to the joint before coupling. Look for it in NAPA or other big box auto parts stores.

Jim, "He who smiles in a crisis has found someone to blame."