I've always hated how long it takes to clean my Q300 Ti tips. Usually just WD40 and a lot of elbow grease, got tired of that yesterday and ended up using bar keepers friend (some powder crap my wife always uses to clean stainless pots/pans, link here).
The shit works wonders. Rag + water + some of this stuff (it's powder, so pre-wetting the rag seemed to be the best way to go) and I pulled more carbon of in one scrub around than I'd done in the previous hour. Pic below is from today (24hr after using the stuff), wanted to see if the residual would harm the Ti at all but looks like a water rinse after using it is all that's needed. Didn't take a "pre" pic, but they were damn near black.
I'm sure someone has done this before but figured I'd share, seriously hated cleaning the pipes but this will cut that down to like 20min now.
FYI... when wet the powder turns into oxalic acid so I'd highly suggest rubber gloves when you're applying it (my fingers were not super happy by the time I was done).