fixx
 

i would do it on the smaller scale by hand and then once you have a hole going through it try to get the rest out with a pic..or just hog it out with a sharp new 3/8 bit..

you could use a pick and have someone hold a shop vac hose right beside.

i am thinking maybe a lag bolt. more of an augur-feedscrew shape...

Fixall is right on, just run a drill through it but i would do it at a fairly good speed to quickly pull the stuff out of there. Do it with no oil in the pan then run a gallon through it with the drain plug open. What little, if any, is left after that will will be picked up by the screen and/or filter. Silicon floating around in an engine is far from uncommon. You should see our Olberg screens after a freshen up on the race motors. Plenty of loose debris and silicone but thats what the filers is there for.