Huh. I've tried Kroil in my molds, and it always caused horrible wrinkles until it finally burned away, just like any other oil. Some guys swear by Kroil in their molds, but I've found it to be pretty awful. I wonder what you're doing differently that it works? Are you just preheating the molds long enough that it burns the oils out?
I've had the same experience with Kroil, and it was disappointing. I am a huge fan of Kroil- I even use it to scrub rifle bores. BUT, in this instance I ended up doing a complete cleaning of the moulds with acetone and Scotch-Brite, then brake cleaner to get the Kroil out of the cavities.
The advice I have always heard was to store moulds with your final casting still in place. It retains the sprue plate and locks your mould handles in place.
Of course, for long term storage one would need to take more permanent steps in dis-mounting the moulds, cleaning, protecting, and storing.
