What spray/lube to use on electrical connectors

I really don't know what you were seeing in the videos, but I do have a very good suggestion for you as far as connectors go. Use WD-40. It does three things for you.

• WD stands for Water Displacement: This means, if you spray it, it will keep water outside of the connector for as long as the WD-40 remains in there. If it's a sealed (or semi-sealed) connector, you'll most likely never have an issue as long as you don't take it apart.
• WD-40 does not conduct electricity: When you put the connectors together, the metal on metal of the connector will allow the electricity just fine, but with the WD-40 in there, you won't have an issue with something cross connecting or electricity bleeding off to somewhere you don't want it to.
• Lubrication: With the WD-40 you won't have an issue when taking the connector apart the next time. It will function as an "anti-seize" of sorts, allowing for easier disconnect. Corrosion will also be kept at bay as well.

Something about water is, pure water does not conduct electricity. However, once you start putting impurities in it, like soap, it will conduct then. Soap will also collect crud (dirt, dust, what have you), which will cause you issues in the future.

For car batteries, there is terminal grease, which basically is a simple grease with corrosion inhibitors. Since it is an insulator, some pressure is required to make a good electrical connection between the contacts.

This pressure makes this grease less optimal for small connectors with lighter contacts. Here, oily contact sprays are better.

But be warned since there are often two kinds of contact sprays. For example, I know KONTAKT 60 and KONTAKT 61 from the german company Kontakt Chemie. The first is a cleaner for electrical connectors, which removes existing corrosion. This is done by some aggressive ingredients, which later will lead even more corrosion. (Like vinegar: can be used to remove rust, but also causes rust) The second product is used after to protect the now clean contacts from further corrosion.

But in general, there often is no need for that special products. Simple petroleum jelly is often used instead of terminal grease, and a simple oil can be used instead of contact spray. They don't contain corrosion inhibitors, but due to their greasy nature, are mostly good enough.

By the way: There is a contact spray form WD40, too, but it is more a cleaner to remove grease, oil, flux and other residues from PCBs etc.

What I think you are looking for is Di-Electric Grease.

Di-electric grease seals, lubricates, waterproofs and insulates electrical connections with a thin, non-curing silicone compound that helps maintain electrical performance by reducing voltage drops and problems caused by adverse weather conditions.

Di-electric grease also provides an exceptional lubricant for fasteners used to support temporary electrical work. 

There are several brands making them. I use it on my boat engine. Search for Contact Spray.

But never, ever, ever use WD40! That thing destroys more engines than saltwater! It is a great spray but not for everything!!! Use that only on metal which is stuck/corroded. Though, Never on moving parts because it DOES NOT have any lubricant in it. It dries things out and it attacks plastics too!