American Flyer tinplate litho bridge

The track should be just fine - I don't see any reason to remove/replace.  As for cleaning I wouldn't use water I'd recommend carnauba cleaner wax.  I use it all the time to clean litho and I've never had any problems.

Just to give you some idea of how well the cleaner wax works - Here's the before and after of a Bing car I cleaned awhile ago.

Before

After

That is the Model 112 Steel Span Bridge first cataloged in 1930. From the pictures I agree with Robert, just carefully clean the tops of the rail and leave it in place.

A word of caution about cleaning AF metal items. I think that water on the early 1930's items should be ok but I would do a test first. After the Gilbert purchase in 1938 some on the stampings use a water soluble ink. I learned this first hand about 40 years ago when cleaning some metal AF buildings with red trim. I started with the 755 station and after two passes with a damp paper towel the red was on the paper towel, not the building. I do not have any early 1930's items to check but I would be cautious of water.

I never thought about a mild cleaner wax. If Robert has confirmed it as safe then give it a try.

Excellent.  Thanks, fellas.