Proceeded to cut out the disc, which then fell forward into the pipe. DAMN! It took forever to fish it out-I thought I was going to have to take the muffler off and shake it out to where I could reach it. Finally using an aluminum angle to prevent the magnet from sticking to the side of the pipe, I was able to get the disc up into the hole I had drilled, but of course I dropped it back into the pipe. After a long tedious time, I was able to retrieve it again, but this time I hooked it with a bent clothes hanger and was able to pull it out. I then used the magnet to pick up any residual shavings that I didn't get on my previous attempts to retrieve the disc. Then hooked up the vacuum to suck out anything left in the pipe.