During my army service, I spent 3-4 years being an AN/TPQ-37 tech. Its a high-voltage, high power, immensely complex Radar. Even though it is such a beast, and could take a lot of mistreatment, we had one "do not use WD-40" rule tattooed into our brain. On the long run it always caused much more damage than help!

DO NOT USE WD-40 WITH ELECTRONICS.

We used to use Freon and silicon based lubricants - but I'm not sure these substances are legal anymore.