Don't clean it unless it looks like it needs it, if it does be very careful and only clean any pins that look to need it. Don't bend any of them or worse snap any off doing so.

Then apply a reasonable amount of dielectric grease to the connector side before plugging it back in, getting the grease over the pin holes so the pins get covered as you put the connector back on.
Apply dielectric grease on any/all connections you check out.