Cork Gaskets

I didn't use any product on my sump gasket, the cork sump gasket doesn't leak. Started weeping a bit when the engine got hot on initial run in, but all i did was lightly tighten all the bolts and it has been fine. In my opinion adding a silastic causes the cork to squash out the sides (makes them slippery), however I always use silastic on paper gaskets. Head gaskets well that's another story...