Problem with destruction to keep the price high gives rise to the question "ARE these the ONLY ones to ever be found?"

So you smash them to keep the price high on the 3 remaining..... Later SOMEONE ELSE finds 50 and puts them on eBay. You have already killed a potential profit of the 23 you COULD have sold and your 3 just plumetted in value anyway. It turns out that price manipulation was never in your control like you thought....

Take the money and run.... if 50 more are found they will be worth LESS than the 23 you put on the market first.

I remember something about "The best laid plans of mice and men...."