I'm onto single wall pipe adjustment #3. Since I've moved things around several times, I have some old holes that no longer line up and need to be plugged. How would I best go about doing that? When the guy did my draft test last year, he plugged it with what looked like a metal thumb tack. I just have no idea of what it was. Right now I just have the screws in there. It's doing the trick, but a better seal would be preferred.
