Source of Keyboard Gunk

My G15 keyboard probably isn’t dishwasher-safe because of the LCD screen so I opted to pop off the keys, put them in a mesh bag and send them through the dishwasher.  This worked quite well as all my keys are now shiny and clean again.  I wondered how my keys got so dirty, not just scummy but dirty having a literal coating of dirt on the 1-5 keys and the Q key.  The answer became apparent when I had to put down the barbeque sauce-coated ribs to do the first draft of this post.  Maybe it’s time to get some Wet-naps.