Cleaning Router's Port Contacts?

WRT54G.

It has been living in a salt water bay front shop for some years.

Owner thinks it's inop.

I can get to the Admin screen and save changes. I can also
connect to it via WiFi as long as port 4 is plugged into one of
my LAN's switches.

Seems to me like port 4 works, but ports 1-3 and "Internet" do
not.

The contacts look nasty: more black than gold.

Is there a non-destructive technique for cleaning these things?

I'm thinking the obvious pencil eraser would abrade off the gold
or whatever the contacts are covered with and make any fix only
temporary at best.

 

Per Brian Cryer:

I'm assuming the male Ethernet cable plugs are bad too - although
I have not seen them. I'll just bring a couple more down with me
when I re-install the device.

Went to Radio Shack, layed out $15.00 for some magic goop that
claims to reverse the corrosion process and it seems to have
worked. *Muy* expensivo compared to just plain old CRC or
whatever the other stuff is though.

Still cheaper than $40-$50 for a replacement router - although
barely if one figures man-hours are worth something.