Just think about how how it gets in the chamber! That should allay fears! Others may worry about moisture, not realizing the chamber, shank and bit are subjected to steam and super hot moisture for the length of the smoke.
I've never raised grain, nor had a mortise swell*, nor a fill pop out due to a very hot tap water flush. Sure, some wax might come off if you run it over the exterior, but always there's enough left to buff up to a good luster.
At this point with about five years' experience on a 80-90 pipes, with 5 years X 365 days X 4 (being the average number of pipes cleaned per day), so over 7,000 hot water flushes.
*Always done with stem in place, unless I am also doing a mortise clean out. Still, no problem with swelling
I've never raised grain, nor had a mortise swell*, nor a fill pop out due to a very hot tap water flush. Sure, some wax might come off if you run it over the exterior, but always there's enough left to buff up to a good luster.
At this point with about five years' experience on a 80-90 pipes, with 5 years X 365 days X 4 (being the average number of pipes cleaned per day), so over 7,000 hot water flushes.
*Always done with stem in place, unless I am also doing a mortise clean out. Still, no problem with swelling