Unidentified Schmutz On My 1959 Jefferson Nickel

It looks like a lamination to me, jdsstrat.

My final five cents on this subject: I think the coin looks worse after the acetone bath. Another lesson learned. Thanks again for all the feedback.

Here's another Two Cent opinion.
The area on the building does look raised but doesn't look like a lamination.

FWIW- I did the same type of soak, with no rinse, on a BU red 1946 Inverted S Lincoln Cent and anded up with the same haze and lost its mint lustre. The grease on my coin wasn't dried out and came off, but ended up in the solution.

You now have an educational piece and I would continue to learn By seeing if I could confirm it is grease by "pushing" it with a cuticle stick. (A toothpick may be too weak and break.)
I would want to make sure it wasn't some type of anomaly to the die.

Could this be from a rusty die?

Just to put a bow on this thread: I was able to push the schmutz off the coin after the acetone bath. So I guess it was die grease, after all.