When a coin looks weak or washed out in random places, most people think it’s worn down. Sometimes they’re right. Sometimes they’re not even close. This is a grease filled die. It happens when mint machinery gets clogged with thick gunk made of metal shavings, old oil, and debris. That paste fills the recessed parts…
A stretched rim with letters slipping upward always gets attention, but it’s not a mint error. It’s one of the easiest forms of post mint damage to spot once you know what causes it and what it looks like under magnification.
Environmental damage happens when copper reacts with oxygen, moisture, and soil chemicals. This 1881 Indian Head Cent shows every stage of that breakdown, from green corrosion to missing metal. It is not a mint error, but it is a perfect example of how copper changes over time.
BIE pennies are one of the most common and recognizable die cracks on Lincoln cents. They form when the die fractures between the B and E in LIBERTY, creating a raised line of metal that looks like an extra letter. They are real mint-made varieties, not PMD, and they make great low-stakes finds for collectors who enjoy spotting die breaks in the wild.
PMD stands for Post-Mint Damage. It refers to anything that happened after a coin was struck. It doesn’t matter if the damage occurred at the mint or in someone’s pocket. If it didn’t happen during the minting process, it’s not an error. It’s damage.