Using Vas. for the pins of the CPU is ok, in MOST cases the pins will never become cold enough to make Vas. do anything adverse. Silicone is ok except for that it will harden up and you will never get your CPU out of the socket after you put it in.
For holding insulation around the CPU or insulation IN the socket, Silicone is the only way to go. But for the pins inthe socket and the pin interface surface, Vas works fine.
