1970 D Lincoln Cent
Struck Through Grease Error
Spiked Head Die Crack Penny
1970 D Lincoln cent errors and varieties exist! For instance, observe the images with arrows noting the errors. Furthermore, spiked head pennies have asking prices for a dollar and up on eBay.com  Moreover, condition impacts value.
Furthermore, struck through error coins exist because of the various equipment applications at coin production facilities. In other words, equipment made up of thousands of parts, from machines dripping grease, to bolts, screws, and random debris in the vicinity, leaves a lot of room for mistakes.
Things come loose, break off, and are accidentally fed into a press striking the coins. However, struck through grease errors are caused by mint employees accidentally over polishing dies.
The grease filled die prevented the coin from striking correctly, hence the missing devices on the penny.
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