I always find it difficult to edit metal surfaces like chrome and steel in Photoshop. When patching and cloning, metal surfaces appear to be even more finicky than skin as they start looking fake with even a minimal amount of editing.

Does anybody have tips for working with metal surfaces? My Google searches only come up with irrelevant results.

Or is the fake look the norm? I've noticed that many metal textures on stock sites look more like an illustration than a photo (probably edited with a surface blur). This look is probably preferable to a natural look where old metal is full of scratches, etc.