PART VI. Striking Errors:

“Struck-Through” Errors:

Struck Through Miscellaneous Foreign Matter:

Struck through metal dust or shavings

Definition: A wide range of foreign objects, from large to microscopic can end up being struck into planchets and coins.  Metal dust is a common contaminant in coinage presses and generally leaves tiny, irregular pits in the coin’s surface.  However, if the metal is of a different composition and color, and if it’s retained, it can easily be seen under a microscope.  When it’s combined with lubricant and dirt, metal dust contributes to a compacted, hardened form of “grease” that is frequently struck into coins.

Metal shavings are also sometimes struck into coins.  These can be broken off rim burrs, many of which are produced a split second before the strike by the feeder mechanism.  Other metal shavings will have different origins from elsewhere in the press and from earlier stages in the minting process.  Impressions of metal shavings are generally curved and fang-like.

This 1945-P Lincoln cent was struck through an irregular foreign object which entered the striking chamber at the same time as the planchet that is represented by this coin. The object may have been a shaved-off rim burr.