This looks like as good a place for this discussion as any.

We are starting to see hardware failures on routers that are deployed in our customer's environments. Specifically, several fan 3 failures. In the latest one, when we brought the router back in and opened it, the level of dust on it and in it was the obvious problem.

Looking within Cisco, there does not seem to be any documentation that talks to doing physical preventive maintenance on routers and switches.

Anyone know if this exists or has developed some guidelines in the past that is willing to share?

Thanks.