phoenix, not because I don't believe youre explenation works, but here are some links to "grunge" text!! Hope the can help when the explanation by phoenix doesn't really help....
http://www.idigitalemotion.com/tutorials/metal.html
BioRUST.com :: Tutorials >> Realistic Metal
Grungy Metal Texture » Free Photoshop Tutorials
well have fun with you're metal!!