Where Does The Wear On A Worn Well Coin Go?

Best not to walk around with one hand busy in your pocket for any length of time.

That says it well.

You cannot rub it incessantly.
You must sleep, eat, relieve yourself, etc., or you won't live to 100.

But for lots of other reasons (among them the fact that human flesh does is not very efficient as an instrument of abrasion on metal), the answer to question 1 is no. I doubt you would be below AU when you croak.

Question 2: The abraded particles probably wind up in landfills or the bottom of bodies of water. For example, if they lodge in your clothing, they get washed out then run down the sewer. Same process if they wind up on your fingers (unless you never wash).

It goes into the ocean along with all the plastic.

The metal as with anything goes into a additional dimension than ours. There are additional dimensions created constantly every time something is done in ours. It is sort of like when you drop something and it sort of just vanishes. It went into one of those other dimensions. This is why you now find something when you look for what was dropped and something else has replaced it. Then sometime in the future your original lost item reappears. That now missing Silver, or other coin metals, simply went to that other dimension so it will then someday reappear but somewhere else such as a Silver mine.
If you followed this and are considering it as fact, you may need help.

This thread has turned into a circus .

we are collectors in currencies we cannot and in some instances will not ever spend.

all we need is one of those tiny cars to have 50 of us pile into and out of in a comical fashion.

circus... uhm, er, yup and glad for it... some of us can be occasionally completely curmudgeonistic!

But too much colloidal silver will make you turn blue. See Argyria.