Use care when putting different metals in contact with each other as electrolysis can occur.

When we got out first Mack fire truck, the compartments were covered with aluminum, diamond plate. A few years later some grayish spots developed - the aluminum had corroded to something the consistency of tooth paste!

Mack told us that we needed new diamond plate and to put a sheet of mylar or some similar material to isolate the two metals.

For small areas, some tough plastic from those packages that you have to cut open works pretty well.