A perfectly innocent 2019 500 Yen piece (not a Reiwa) gets subjected to a entire series of chemicals and scrubs, apparently to give it a mirror like surface. Yikes. Other coins receive the same treatment: The 50 Yen is a Reiwa...
Interesting. Each scrub probably starts wth a very fine abrasive with the following srubs being much finer.
That's some pretty skilled polishing to give such a prooflike appearance without dulling the surfaces and leaving a bunch of hairlines. Some of the old-school coin doctors who whizzed coins back in the day were similarly skilled.
You will also note that on the early "scrubs" he concentrated on the fields and avoided the details, probably so that when he moved to the very fine grits it didn't polish the details as much. He also avoided the design shifting features in the numerals. You don't get the hairlines due to the extremely fine grit used. This would basically be the same way the fields of the proof dies are polished, he may even be using a finer grit than they do. (only they use a rotating lap because the fields are the high portions) You don't see the hairlines from the dies on the fields of your proof coins do you? All polishing is done using abrasive grit, the result is just a matter of how fine the grit is, get it fine enough and you can't see the polishing lines anymore. The lines are simply finer than the resolution your eyes can detect. For those that have polished scratches out of their slabs, the final grit used in the plastic polishing is probably about the same as the starting grit he used on the coins. This is probably how they used to make the "California prooflike" Morgans. Polish the fields like this and then artificially frost the details.
