Cleaning Copper Contacts?

Dwight K. Elvey dwight.elvey at
Mon Oct 3 11:23:43 CDT 2005

 I recommend removing the oxides as non-abrasively
as you can. Try the eraser trick but for stubborn
oxides, I often use a stiff piece of wood, like
a popsicle stick and water. The oxide itself can
be abrasive so make sure the rinse the loose stuff
 The green oxide can be from copper or nickel.
 Once you have the surface clean and dry, use a little
of the DC#4 to coat and protect it from future corrosion.
( See earlier post on subject of DC#4 )

>From: "Martin Scott Goldberg" <wgungfu at>
>>>My concern is I don't want to use any sort of cleaner that will harm
>>>whatever material the surrounding pcb is made of (as it appears to be made
>>>out of an older, thicker material than most modern PCB's I see).
>>If the underlying material is copper, why not one of the ion-exchange instant 
silverplate solutions like Cool-Amp or Caswell Silverplater?  They deposit a 
very (one molecule) thin layer of silver that might do the trick for a 
restoration.  Caswell also m
>arkets brush-plating electrolytic silver (and nickel, gold and a whole bunch of 
other metals) kits if you'd like something more substantial..  
>The exposed copper doesn't look to be underlying.
>Well, here's a pic of what the cart and connector normally looks like -
>As you can see, the PCB is much thicker than a standard PCB of today.  I'm
>assuming its made of a different material then (which is why I'm hoping
>people on here in to mini's and such from that period of around 1972 would
>be familiar).
>The contacts themselves are what are tarnishing and turning green, some
>with white deposits.

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