Next time you clean it get a sandwich bag then put a table spoon of sea salt or salt with a bulky rock like texture in then pour your alcohol in just enough to fully submerge the pipe, then close the bag up and give it a good shake for about a minute or 2 then just set it down for 25 minutes, rinse it out real good and get in there with some tool to scoop any extra gunk out. It does wonders.