Always be prepared and have a few Q-tips in your pocket along with a small pack of kleenex.
Well, that is if you have to a personal stash to resort to. At some venues this having a purse full of hygeine products is a luxury and certainly not always a pre-planned matter.
Now, the USCF does have conventions in this area. Granted, they are guidelines rather than rules written in stone. Considerable thought and debate has arrived at easily remembered associations. Specifically size & configuration board symetry is taken into account when delagating certain pieces to specific orifices.
For example, here like in Wales, the bishop is used on the auditory canals. The piece conveniently comes tapers at the top for these smaller orifices. So as not to spread infections from one to the other, usually the dark-square bishop is used for left ear (your own ear, looking forward at the board) while the light-square bishop is used for the right (again, your own).
Another example, pawns are used for the nasal passages becasue there more of them and they tend to be used one time only, so no concern for transference here. Again, the Golden Rule here is that you can pick your opponent, and you can pick your nose, but you cannot pick your opponent's nose.
Now the there is only one Queen and one King. And there are other cavaties in the body that do not have the symmetry as the ears and nostrils, but it is utterly important not to mix them up - much like mixing the specialized thermometers in the hospital. The major difference, of course, being taste. Or smell. Whichever is more convenient.
Hope this helps.
When are you allowed to touch your opponents pieces?
with the wax on it and looking like michael Jackson I think you wrecked its moonwalk - you did not deserve to win.