wiper motor

[john rod]

after reading the post about wiper motors....I got busy and wired up the one I got at the salvage yard. it worked and parked. so I tackled the original in my Panel. it had lost its ground. if there is/was a brass ground strap, it is either on the top mounting bolt [where you cant see or get to] or there never was one. so I added a new ground wire. and now the motor runs and parks!
however the wire connector at the switch is a mess. sometimes it works, sometimes it needs a wiggle. I took the switch out and dipped the brass terminals in M. Acid, then sanded them. no difference.
the questions is now, how do you clean the brass terminals inside the plastic connector [especially that the wiring barely reaches the bottom of the dash] ?
drivers are dangerous here in dry weather, I would never drive my Panel in the rain. still I want everything to work properly.
thanks Rod in AZ