I spray the 7-pin trailer-to-tow-vehicle connector yearly with silicone spray.
Dielelectric grease, BTW, is silicone based.
The use of a spray can, IMO, will rinse out debris.
Caution is warranted with too much connector sanding
. Most, if not all, connectors are plated. I.e. a structual base metal will be coated with a more conductive material. Sand past the coating and you're in trouble.
I learned this the hard way with the multiple relay contacts on my first reel-to-reel tape transport. Sweet unit - triple sychronomous motors with the only moving part being the pinch roller.
Worked like a dream after the first time I sanded the contacts.
Ten or 20 reels later I was back to square one. More sanding/cleaning. Five or ten
reels later.... you get the idea.
I replaced all the relays (no small cost issue for a teenager), and had no more problems.
If you are worried about oxidation, I recommend nothing more harsh than 600 grit sandpaper.