I have 2 Rossi's, 1 Savinelli, 1 Grabow, and 2 MM cobs that take filters. I started using filters and then quit after I smoked one pipe without a filter.
I tried them a few times years ago. Found them to be a pain and found no pluses to their use. I tend to smoke dry and do not exhale moist breath or, deposit spit into my pipes.Next question should be if people who dont use filters have tried them
I'm using 9mm filters with my pipe and looking at them after just two smokes I feel like everyone should
But if you had a double long shank that allowed two filters in a row, the second filter would be discolored, too. Clearly you haven't yet achieved the goal of nothing at all coming out of the pipe stem.
If not directly inhaling, there's negligible concern for that.the less you'll have in your lungs.