I use worm oil to lightly rub onto a cold mold...or a mold with fine tails/legs to help with flow and get the mold to fill.
A good example is the spline on the Tube baits. Until the mold/spline gets hot enough you can get short shots on split tails...but a little worm oil and the fill really nice even on the first shot.
Worm oil also works good to rub off "permanent" marker of my small plastic boxes ...which I use instead of bags and mark what baits are in them.