BANKSY - silver spring

I've seen TV documentaries of the highest forms of graffiti art that are painted over after viewing. What is the the name of the NYC graffiti arist that sells works for 5 figures?

Pigments mixed with egg yolk (tempura) can last thousands of years.

Egg whites can weather seal old wooden instruments on te inside.
Today I use 1 micron thick glass which transmits sound the same as spruce.