[Leo.G (Leo)]

You can wrap a little fine steel or brass wool around something like a Q-tip and gently clean the contacts in an in/out motion (not around and around) but ensure you don't bend the contacts up or leave the dust inside the connector when you've finished cleaning. A camera blower bulb should remove the dust if you don't have any sort of blower (and the wife protests when you try her hair dryer, lol) if you choose that route.
While contact cleaner is good it won't get all of the corrosion, you'll still need some sort of brush/abrasion to assist. If you have a hearing centre near by (or a hearing aid) the little brushes which come with these can be had cheap and are amazing for this task as they are very small and reasonably stiff bristled. I'm lucky enough to have a few laying around, not lucky in the sense it's because my son is deaf (formerly partial, now close enough to fully).


EDIT: Disposable nail files, little paddle pop sticks with a fine and course side, cheap at Reject shop I'd suspect.

I restore a lot of old, worthless junk (mainly for myself now), serviced TV's VHS and sound equipment and basically anything which involved electronics including industrial crap (and designed and built crap) for a lot of years and I'm always on the lookout for small convenient aids, I forgot about these things.