Al;

ACZP* is commercial electrical grease (but not NOT DIELECTRIC!), required by electrical codes when connecting copper and aluminum conductors, to prevent galvanic corrosion...just because the term dielectric has "electric" in it does NOT make it suitable...DIelectric means: INSULATOR. Do not confuse the two! Putting an insulator between high current terminals, particularly like those in a 6V system, is not what's needed.

...and although any grease (including axle, or Vasoline or Dielectric), will encapsulate a connection and for instance keep any new moisture or battery acid from getting to the connection, it will also keep IN any moisture or corrosive agent which was included when the connection was first made, allowing this do do its dirty work...Baaaad!

That is why I recommend against the use of DIelectric grease. I do recommend using ACZP! ...because ACZP will prevent any new corrosion from starting, and stop any corrosion already in place because it acts as sacrificially to neutralize chemical reactions occurring between the main contact materials.

* You wont find ACZP per se anywhere because this is a generic term I use, short for Anti-Corrosive Zinc Paste (for further info and details, see: http://www.sw-em.com/anti_corrosive_paste.htm). The commercial name-brand I recommend, and what you want to ask for by name at the local commercial electrical supply house (not H*** D****) is: Penetrox by Burndy.

Electrical manufacturer Ideal also markets an anti-corrosive product and you will find it around, but this (honey consistency) material is much too low in viscosity ...it runs away from the application site (and that at room temp...it probably mimics melted butter at elevated or even engine compartment temps!), which makes it worthless for our needs, whereas the paste-like consistency of Penetrox keeps it it place (even overhead!)

Hope that makes it clearer, cheers!