Found this sign in my buddies antique shop on Sunday. One side looked good, the second side was all covered in spots of some kind. I could see a couple chips on the outer edge but did not see any in the field. I was hoping the spots would come off and they weren't hiding anything. Another guy made an offer on it that was $200 under the asking price. I knew it would go quick if I didn't take it so I traded a duplicate sign and some cash for it and took it home.
Couple pictures of it as I bought it;
You can see the heavy shelving and some of the spots
More spots and rust staining
Not sure what it was
I got a couple SOS pads, a cold one and some windex and went to work.
Starting to clean up. The spot above the D in the blue border ring about the size of the tip of my pinky finger took over 600 back and forth rubs with an SOS pad to get it off.
I got the spots off but not all of the rust staining
I didn't want to mess it up so I tried some Barkeepers Friend on it. I figured that was not as strong as Muriatic acid. It cleaned it up pretty good