Die polish

Not really. Even though the design is incuse, the high points of the coin are still on the devices, meaning some parts of them are still at a higher level than the fields. Just not all of them are like on a relief coin.

When dies for relief coins are polished it is done on a machine that for all intents and purposes is kind of like a belt sander. The surface of the polishing belt is flat, and all thewy have to do is hold the face of the die against it to polish the die. That's because the face of the die (the fields area) is flat too.

But they couldn't do that with the incuse designs. They had to use small polishing tools with little buffing wheels because the design stuck up higher than the fields in some places. This made it much, much harder and much more intricate process to polish these dies.