Prefer my coffee strong and black - Chicory!
Come to think of it, maybe the cup needs a scrubbing with Hoppes #9!
Caffeine is my shepherd; I shall not doze.
It maketh me to wake in green pastures:
It leadeth me beyond the sleeping masses.
It restoreth my buzz:
It leadeth me in the paths of consciousness for its name's sake.
Yea, though I walk through the valley of the shadow of addiction,
I will fear no Equal™:
For thou art with me; thy cream and thy sugar they comfort me.
Thou preparest a carafe before me in the presence of The Starbucks®:
Thou anointest my day with pep; my mug runneth over.
Surely richness and taste shall follow me all the days of my life:
and I will dwell in the House of Juan Valdez forever.
Amen
(don't know what this has to do with firearms, but everyone needs a chuckle now and then.)
To steer back to topic...
In regard to coffee as a cleaner: I'm not sure what the percentage of content is, but coffee does have an acid component in it, and maybe, just maybe, that has a bit to do with it's alleged cleaning properties. However I agree with several other posts.. it's the 'boiling hot' that does most of it. and yes, very hot water and soap is the best BP cleaner i have used. Besides, if you heat the barrel properly by using a large quantity of hot water during the rinse, it will flash dry. Less chance for rust!
Oh... and there was a WW1 gas mask called a "smelly duck". You had to urinate on it to make it effective though.