Joe P. writes: I read about the doubled die coins and other mint mistakes, but what if the coin is missing a part of the date? I have a 199? Lincoln penny. It looks like the die didn’t press hard enough or something. The coin is in very good condition, so the number isn’t worn off. At least there are no signs of major wear on this coin to these eyes. I also have a 1998 penny where the 98 is barely readable. The nine has much more presence than the 8. Again it looks like the die didn’t press hard enough. Would these coins be worth anything one day you think? Thanks.
Your missing digit is a filled die error. Generally, missing digits or mint marks on modern coins are due to filled die errors where dirt, grease or debris fills the recesses of a die not allowing the number or mark to strike up. The metal from the blank can’t flow into that area to receive the impression. This problem usually only lasts for one or two coins until the foreign material falls out of the die.
The coin would be valuable if the die that struck the coin was missing the date digit or a mint mark. That means that others would exist creating a new variety, not unlike a doubled die, where the flaw is in the die and every coin struck from that die shows the same error.
Filled die errors are common and inconsistent and add no value to the coin unless the filled die error is severe.