This page was created from Joel's Interactive Guide to Straight Razor Shaving and can be discussed in this thread.
When/where to use metal polish, and where/when not to!
Flitz, Mass, Metal glo... all useful products... and all work about equally well. However, how do you know where, when and why to use them? Well, let's first start with why. Using a metal polish is done primarily to remove rust/corrosion from your razor. It however can also be used to lightly polish up certain types of razor scales, and brass inlays on razor scales (such as the ducks on a dubl duck razor), which will bring them to a brilliant luster.
When to use a metal polishTypically you'll use a metal polish on old eBay razors to remove grime, rust and corrosion. Often, you can turn a pretty homely looking razor into a gleaming beauty with some metal polish and elbow grease. Less frequently, you might use metal polish to remove a stray water spot on the blade, which would be a more precise application, whereby you'd take a very small amount of polish and put it on a Q-Tip, and lightly rub the water spot out of the metal.
When/Where NOT to use metal polishBasically, you'll want to shy away from using metal polish on any gold wash on the blade or spine, and/or light etchings on blades, as often - metal polish will quickly swirl and remove these pretty attributes.