Antenna Mounting - dissimilar metals

[macrafic]

I had once read somewhere that a conductive anti-corrosive paste/grease should be applied to the threads of the steel bolts/screws used to attach the antenna to the aluminum skin, thereby preserving the ground plane but, at the same time, addressing the dissimilar metal corrosion issue.

For the life of me, I can't remember (or fiind) the suggested paste/grease. Any suggestions out there?