Foot Starter Switch Lubrication?

[PT81PlymouthPickup]

Getting ready to install my new starter switch. Anyone know if the contacts should be lubricated or left dry? When I took the switch off there was a black grease that had definitely been applied to the copper contact surfaces. I rebuilt this starter 35 years ago, but can't remember why I lubricated it or if it was even supposed to be? My dad, a professional mechanic was alive then. I'm thinking he may have suggested lubrication? I'm wondering if it may have been some special lube? I was thinking of applying a light coat of anti-seize? Thoughts and opinions welcomed! 

[LazyK]

A thin coating of dielectric grease would prevent oxidation.  other wise I would leave dry.

[Mike Fix]

I don't know how available it is anymore but there is a blackish colored "grease" that has a high silver content. It is made specifically for electrical contacts. Because of the high silver content, I'm sure it is pretty expensive if it is available at all. Leaving them dry will be okay too.