No Razor Blades!!! Sounds like it may be a painted tin sign. DO NOT SCRAPE IT! It all depends what they used to paint over the sign. If it was a water based latex paint... you're in luck (maybe). Use a generic paint remover... gently, and wipe carefully to expose the original patina. Beyond that... you may have a problem removing the overcoat without harming the original sign... You bought it at the right price. Good Luck, be careful, and you may find a real treasure under the surface.
------------------
Frank
