To avoid losing the little blighters, I have been accustomed to holding valve caps fastened to my tongue while using the valve; this is quite easy and done by creating a little suction. The method can be used for up to 4 caps simultaneously, perhaps more with a long and sinuous tongue.
Having read this thread thoroughly I am now concerned about several issues which are beyond my technical competence, and perhaps the wealth of professionals here could offer advice.
Firstly, if someone, perhaps a pilot, asks me a technically important question when I'm encumbered with the caps, the reply may not be very clear, and can sound like "uh oth". Now that we are introducing SMS, should this be considered a risk?
Secondly, is there a possibility of an adverse interaction between saliva, itself perhaps contaminated with a number of chemicals, and the gas in the wheel? If so, is that a risk, too?