Can dielectric grease be used in coax connections?
Living and working as a cable television technician in a beachside region, I can attest to the value of the silicone dielectric grease for improving the lifespan of these connections. Salt air eats everything in time, yet the grease prevented corrosion after five years. The fittings were assembled with "boots," rubber covers which resemble spark plug wiring ends. The grease was applied liberally, inside and out, and the boots then slid over the fittings.

Sun, salt, sand and wind would eventually deteriorate the rubber, but even then, the fitting within the mass of grease held up quite well.