I just did mine. I used electrical contact cleaner cause it dries almost instantly and leaves no residue which I figured carb cleaner would. It was black, kinda oily. Cleaned right up. Also use an ohm meter to check it. At room temperature, it should show 10,000 to 12,000 ohms. The o-ring will seal it right up as David C said.
PS: I'm 6'-0" but find that standing on a 1' tall block of wood makes getting to this thing much easier. I took mine out in about 1 minute with a deep well socket, and an extension. Be careful with it. It looks somewhat fragile.