Hi This a a great guide and gave me the confidence to tackle the barely working, right hand, rotary switch on my Yeti.
When I had dismantled the switch I found that it was spotlessly clean and thought there would be nothing needing to be cleaned. I did however clean the U shaped optical switch with IPA on a cotton bud and removed the thumb wheel to check the little windmill on the end of the thumb wheel. This interrupts the optical switch when the thumb wheel is rotated.
After re-assembly the switch has been working correctly for the last 4 weeks. I suspect that there is a component problem on the circuit board or may be a design issue, as just a wipe with a cotton bud shouldn't have made that much difference.