Looks like an acid bath. Wire wheel would have moved the metal so that it looked double or triple. Capped die would typically only affect one side.
I will wait and point out my observations after more folks post. There is a characteristic that is being missed.
The somewhat puffy look to the lettering and wrinkled appearance that resemble radial flow lines kinda make me think capped die(s). Weird but I still said acid bath lol
Wire wheel. Acid bath will dissolve all surfaces evenly, wheel will remove some of the design depending on how long it was held in one spot. I have found that not all wire wheels leave the same pattern due the coarseness of the bristles. Some are made of steel and some are brass. The softer brass wheel have more tendency toward leaving a doubling effect. Note saw tooth edge at 3k and 9k on the reverse, and none at 6k.
I'm leaning towards wire wheel, but won't be upset if I'm wrong. Sand Blasting is also a possibility IMO
Sand blasting would have had more affect on the details. And, I think you would be able to see the sweeps.
The answer Well, the coin has been hit with a wire wheel. Acid doesn't leave the rims looking like it has dentils. nor does it build up material at the devices. Acid deteriorates a coin evenly leaving a blurry under weight coin.