So I bought a new 12mm - 14mm adaptor closed end shower head down stem. I clean it on a regular basis but recently it has been building up a residue that I cannot get rid of. There is a brown resin building up about halfway down the stem and right at the bottom at the shower head. Usually I clean it with 99% isopropyl alcohol and salt (shake it around) and that get most of the other junk, but not these two built-up areas. I have tried soaking it for an hour an attacking it with pipe cleaners, but even that didnt help.... Any suggestions?
Maybe hard water stains? Don't know what's going on without more information. Try some vinegar, that helps with hard water stains.
Definitely brown resin stains. Almost seem to be baked on if you will. 99% iso and a stiff pipe cleaner doesn't even do it....