Dang! And here I hoped the question was about what to do with a dirty plate after the meal…
…where I would say that the best compliment to the hosts is to lick the plate clean and ask for more food 
Hold the offending object up in front of your face, spit on the visible mark and then scrub it off with either a hankie or the cuff of your blouse/jacket. Then swap it for your husband’s implement.
Drop your serviette where the person next to you (preferably your wife/SO/life partner) can pick it up, then while they are bending down to get it for you, swop the dirty item with theirs. You may need to distract every one else at the table while you do this - pointing at the ceiling and saying is that a leak/bird/ufo/whatever? usually suffices.
Observe how the person with the dirty item now handles the problem. File in mind for next time. 
Si
Let’s say you’re invited, along with a small handful of others, to a dinner party at the house of someone high up in the pecking order at your place of work - a director, or something. Dress code is smart, so it’s going to be an occasion where you need to follow proper dining etiquette.
BTW, this isn’t anything that’s happening to me - it’s just something about which I was idly curious.
Slowy pulls middle finger out of the nose and with an expression of utter obliviousness:
-So?
[Euell Gibbons]
“Many parts of the Fine Bone are edible.”
[/Euell Gibbons]