I live in a very damp area, so I store all my ferris based moulds in Kroil. As a preservative. Used it before I ever heard of the Great Kroil controversy. Because we use it in my industry .
That is the product we spray down our iron moulds, going into long term storage(like over a year). It requires no removal but running over a gas flame before we bone ash.
I just burn it off before I start casting. Easy peasy.
I don't use it for its casting properties, but to keep my moulds from rusting.
A few wrinkles, first five casts or so then no issues. If I use a hot plate for a bit first. I get good bullets in about 2 casts.
However Had an issue with one mould. A Lyman two cavity mould that I was at least the 4th owner of.
when I got it I cleaned it really well. Mistake... Stuck like it just did not want to give the bullets up. Cleaned it up then put it away in Kroil.
After storing it in Kroil. Well it never stuck again.... Ever.... Haven't cleaned it since with a out 5 more casting sessions on it.
So I guess I will never know that it don't work, as all my Mehanite moulds swim in it, between use. And none of them ever stick.