Contamination on gold plated switch contacts

We are experiencing contamination on gold plated switch contacts at the point of contact. What's your recommendation?
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The following link describes the same problem we are experiencing: http://www.reliabilityanalysislab.com/Contamination0102.asp

The contamination builds up over a fairly short time (3-6 months), and occurs in a few cases, in widely varying locations of the world, and has a varnish-like buildup, but only at the points of contact.

Our keying system uses +5V, and we have tried increasing current from 7ua to 2.2 ma, with no change in time for build up of this substance noted.

Have your technical people seen this type or contamination, and can it be prevented?
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I reviewed the link, and based on that, I recommend the DeoxIT® contact cleaner. It's formulated for precisely the application described.

Additionally, we would be happy to contact Dave Pinsky, the author of the Raytheon article, and offer a resolution to that application challenge.