When I worked for General Motors, Kroil was all we used. Almost everything I used it on was indoors and never severely corroded. After what I had read about Kroil, I expected great things. But many times, even after very long soaks and repeat applications, I would find that it didn't penetrate very deep, and the fastener had dry threads a short way down.
I never tried Mouse Milk, although I did note a few strong recommendations for it when I searched around more for references to Oil Of Wintergreen as a penetrant. I'll probably end up trying it unless the Wintergreen proves to be far above everything else I've tried since Cabot's Tasgon was removed from the market. It contained creosote, smelled very bad, but worked miracles. I have a small amount left that I only use for extreme emergencies.
Other than long experience under different conditions, I don't know how one could fairly evaluate penetrating oils. If I try four or five brands on one stubborn screw before I break it loose, how do I know one of the earlier ones didn't do most of the work?
