You might think about possibly disassembling them occasionally to clean out the mortise. That's where stuff accumulates.
I make sure to rest my pipes for at least one day after smoking, put them away cool and then disassemble before the subsequent session. Thereon I check to see if the filter needs changed, run a pipe cleaner up the stem and draught hole and then carefully use said cleaner by going around the diameter of the chamber with careful vertical strokes. A bit anal retentive for some, but an ounce of prevention is worth a pound of cure...
@burleybreath one day I'd like to expand my pipe collection, at which point I'd have a senior reamer for my rotations. Pipe restoration is something that appeals to me as well, so I'd see a more durable reamer as part of my inventory when I happen upon intensely thick cake.
@mso489 I vaguely recall something like this from some years back. I'd imagine using paper towels would give a uniquely thin and smooth interior layer to the chamber.
@anotherbob for sure, I'd be like a surgeon if I were reaming pipe bowls. I'd kick myself if a lack of patience marred or ruined the briar.
Thanks again for the myriad of thoughts in the thread everyone.