Ha.
I had this recently, lasted for a few months. I *think* it's gone now.
It started when I would lick my fingers after eating something, and noticed "holy shit, my fingers are bitter!"
And then, I started testing other skin surfaces. I'd taste the skin near my mouth - nope, nothing.
Lick my upper arms. Frequently, they too were bitter. Sometimes, they were not.
I too scoured the 'net in hopes of fingering something. But here's the catch - I've never used any canned air in the past handful of years, nor has anyone used any canned air or hell, cleaning chemicals, on my computer desk (then at my apartment on campus, now I am back at home).
I don't know what it is, and I cannot really say I've changed much. Recently, I noticed I might not have been getting as much potassium in my diet, as now I am eating more regular home meals and going out to eat at bars, versus then I was eating mostly campus food (which is likely loaded with vitamins to ensure the kids who are strictly on campus food get what they need). Maybe there was something I was something of which I was getting too much?
Hell if I know. Still taking the same pills, same supplements... I have cut back on caffeine a little bit, as I was consuming probably far more than I should.
And recently I have made a pledge to drastically cut back on sugar intake, trying to change my entire diet to focus more on fatty acids and proteins and severely cut back on carbohydrates.