Got this 2009 D it is very faint, and almost looks like the D is double. The rest of coin doesn't look too bad or worn. Just wondering if this is something common, or if this has any possible value/collectibility. thx. Mike
Looks like a grease-filled mintmark. Doesn't really add too much value, but cool to see! These errors are caused when grease gets stuck in the die and causes the mintmark to become faint. What's funny is when these get extreme enough, the D becomes completely invisible, and it is indistinguishable from a Philly coin (Before they had mintmarks). In 1922, only Denver made cents, so these grease MM errors are very valuable that year because they could be identified as errors and not just another philly coin. Great find!
Edit: 2009 is a low mintage year for nickels, so it's worth keeping regardless of the error.