2006 P Jefferson Nickel Clash ?

Not a clash, maybe a stain, or some of it could be strike through grease.
Need to know, is it flat, raised, or incuse?

@Dearborn Looks like they are very slight depressions. Incuse the best I can tell.

I think @ijn nailed it.

So if incuse, them my thought of it being a strike through may be the correct one.

I do not think was grease here but a struck trough a detached clad.

Unlike the grease strike that affects the devices, the grease with grit in it is so far just on the surface of the fields. (outside part of the die. When wiped down, then it gets into the devices and starts to block the striking on the devices. Only way to fix that issue is in the machine shop when they work on cleaning the die. (Or ignore the issue and the coins will remove it a little bit at a time) Just depends on the machinist.