I capped mine just like the sewer skewer and then drilled holes through the horizontal section of the T. Very similar to the sewer skewer. Because of how corrosive H2S gas is, I used heavier copper, soldered al the joints and ran two stainless self screws in at each joint for insurance. Directions on the sewer skewer say to replace them after 2 years but if you look at them they are pretty light copper. Maybe that's the key but I figured mine should be good for atleast 5-years. Maybe I need to redrill and increase the hole sizes in the T? IDK, maybe the lighter copper is the key. in any regard, I still had the one trouble vent freeze up once this year with both the insulvent and the 12 foot copper T!