An old machinist friend of mine who's in his 80's now brought me this sign today. He knew I've been collecting a while and wanted me to give an opinion on this. He said he's had it sitting on the ground behind the surfacer in his shop for over 40 years. I haven't cleaned it or anything yet. I'd like to make him an offer on it, but I'm not familiar with Wolf's Head Oil sign values. It's a little dirty/greasy from being in the shop for so long, but I know it will clean uo nice. Has a few sctatches, but still displays nice. What's everyone's opinion on value and age for this? Thank you in advance.