So I live about 3 K from the beach - and I am too lazy to take the boards out of the Combi. So for some months now my 2 foils have remained assembled and un rinsed in the back of the van. I know - dumb idea right? How dumb? well 3 screw drivers later ( Phillips head contacts just are not built for this) I just managed to get the stabiliser apart - but the M8 into the mast from the mount plate is never coming out - even an impact driver shattered on me. Interestingly the naish anodising seems really high quality - it was fine after about a month - no sign of corrosion. I wouldn't mind but I bought a giant tub of lanolin - which never got used!
May be hard if all is stuck together, but if you can soak it in "HOT" water for quite a while and use an impact driver with a good quality piece (ensure it's a #3), and most importantly give it a hit in tighten first before trying loosen. I find 99% of the time this can work amazingly.
Anti-sieze's are great, but you can;t beat regular dismantling and washing your foil.
Good luck with it all.
Kind regards,
JB