Rolled In Metal Mint Error
Rolled in metal or metal inclusion occurs when a piece of slag metal falls onto the alloy stock and then the stock is rolled into coil stock the same thickness as the intended planchets are to be cut out. This process also flattens and spreads out the piece of foreign slag creating an obvious area of contamination.
Note: Heritage is calling this improper metal mixture. So this is similar in nature, when defined as such, as improper alloy mixture.
Not many price examples on this type for other denominations but the coin in the image above sold for $402 not including the 10% buyer’s premium. It is a 1944 Lincoln Wheat Cent.
Image courtesy of Heritage Auctions