On Wed, 8 Jul 2009 01:38:40 -0400, "Wild_Bill"
wrote:

snip
Getting something to run briefly, or for evaluation purposes is one thing..
but using abrasives on contact points shouldn't be a regular service
practice, IMO.

If I had a nickel for every contact I have filed through the
years...

It depends on the contacts. If they are gold plated, special
in someway, you need to be careful and try not to remove the
plating. For that type of contact I usually just settle for
cleaning them with some thin cardboard/folded over paper
maybe soaked some in rubbing alcohol. Dry everthing
thoroughly afterwards.

For anything else I have had the best luck using anywhere
from 80 to 320 grit sandpaper folded over. Most of the time
I would fold a thin piece of sandpaper over my burnishing
tools blade. I found the burnishing tools alone to be pretty
much worthless, but they work well to support a thin piece
of sandpaper. Use a pair of hemostats to clip down on the
sandpaper-burnishing metal and clean/sand away.

When you get done with the sandpaper replace it with a piece
of folded over paper and clean some more. When you can run
the paper through and it comes out clean your done. On
smaller contacts/relays you may need to tweak/adjust the
contacts a little. There should be a little bit of wiping
action. This can be tricky and if you have a working or new
relay around, it would be worth studying it first to see how
much is enough.

For the most part this would give like new performance,
often times lasting as long as a new replacement.

The problem I saw most often was that people weren't
aggressive enough and didn't take the burnt area down to new
metal. A bit of pitting doesn't bother much, don't take off
more contact than necessary either.

--
Leon Fisk
Grand Rapids MI/Zone 5b
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