Cold weather: engine 'scratching' sound?

1995 RS

Another little nuance since moving NE from Austin. During the really cold weather, right after I start the engine, I get an annoying 'scratching' sound from under the hood for about the first five minutes until the engine warms up. Sounds like somebody dropped a marble into a garbage disposal.

What the heck causes that? How do we fix that?

Thanks,
MC