Dow #4 Electrical Insulating Compound

http://www.dowcorning.com/applications/search/products/details.aspx?prod=01903128

It's called an insulating compound.....

MTV

My opinion, only a non conductive grease (dielectric grease) should be used on multi-prong connectors. A conductive grease could cause voltage or signals to travel to wrong conductors. There are many silver or copper based "conductive" greases available for single conductor connectors.
Clean, good fitting terminals & connector's with dielectric grease have never let me down.
There are all kinds of terminal & connector cleaning kits available.

I was at my I/A renewal seminar this year and the Fram rep was talking about using it on oil filter O rings to prevent them from sticking. He said clean oil is ok but this grease is better. He also said using a little dirty oil on your fingertip will make it stick like crazy glue

The types of connectors that typically need DC4/dielectric have precision fit pins that make good contact. The insulating compound is to keep moisture and oxygen out.

DC-4 is a dieletric. Means it is non conductive. It's also way to thick to use on any precision pins/sockets. It does work well to pack into non sealed connectors like molex types. helps to keep water out but it WILL attract dirt. You want a product called Deoxit. It's not actually conductive. What it does is keep the surface of the metal from oxidizing so corrosion can't start. I believe there are at least two different grades. Depends on the metal in the contacts.

Web

I use it on the rubber part of the spark plug connector lead. Keeps the rubber from sticking to the spark plug barrel.