[Joe K]

There are two types of "gook" you can put on it. Using both maximizes your post to clamp contact AND insulates the surface against trickle.

I use Noalox conductive grease on the post/inside of the clamp. This is a product which became popular in the 1980s when many new houses were wired with aluminum wire. Aluminum DOES corrode and the oxidation is thin, but an effective insulator/resistance to current flow. Copper contacts against aluminum yield a "hot-spot" which burned down MANY houses until the wiring manufacturers came up with a conduction solution. The solution was to use an air excluding "conductive grease" of which NoAlox became the primary name among electricians.

On battery terminals, the grease part prevents the thin film of lead oxide from forming and the graphite within the product provides a non-interruptible current path.

Then - when the clamp is in place and snugged up, spray it externally with the yellow spray frequently advertised to eliminate "trickle current" which is the source of the blue/white powder. CRC Battery Terminal Protector is what I have now although CRC sells a gel that can be used, small felt circles infused with the stuff too.

I have been known to wash a battery particularly the top with soap and distilled water (which can come from the dehumidifier) to reduce the trickle.

Doubtless there are other names for battery products to prevent corrosion but you want to separate the conduction issue from the trickle current issue since technically as issues they are at odds with one another - and one product alone is unlikely to solve both.

Joe K