When the nimrods who did so installed my St. Croix Revolution furnace. one of the things they did do right was put in two double-tee cleanouts. There's one inside right behind the furnace that goes horizontally into the furnace and vertically starts the run to the outside. There's one outside which makes the horizontal to vertical transition out there. On the inside one, they ran a layer of silver HVAC tape over the two cleanouts (they didn't do that on the outside one). I haven't seen anything like that on the various pictures of other's installations I've seen here, is it a normal practice? It's not that big a PITA to peel it off to get the cleanout covers off and put some back on afterwards, but if it's a step I can skip maybe I will. The caps are held in with a single screw once I get the tape off.