This will be my last comment about this. I asked Rick Snow and I got this reply in a record setting 15 minutes. I have had dealings with him in the past and even have coins that he attributed in his book.. Here's what he had to say:

Sorry, I should have known not to join a chat room sponsored by a grading service and bring this up. CYA

@Mikhail2400  I guess us old timers and serious collectors are behind the times. We never thought of altering coins to make a profit. We take the coins as they are, which we think look fine. Pretty soon all you'll see are all blue-brown coins in plastic holders. It's a shame.

@zadok Sorry, but, me and a lot of others on a couple of coin chats, disagree. It's not conserving, it's enhancing. If I sent the coin in as it was, would I have gotten the grade he received? Especially the MS66 which is totally outrageous. 

  Nobody's answered my question. Is it ethical? It's ok if you don't get caught?

@Quintus ArriusWow!! He's been a "member" for 20 years. I've been collecting, selling, buying coins for over 40. What's your point?

What does politics have to do with it? I'll admit I use Blu-Bow but it doesn't chemically change the surface of the coin or make it appear to have original mint luster. Capitalism? SMH

I sold two items to someone and he did something to them and then sent them to NGC and now he is reselling them.

My listings: 

https://www.ebay.com/itm/403046556866

https://www.ebay.com/itm/403086237791

His listings:

https://www.ebay.com/itm/185068890161

https://www.ebay.com/itm/185072612143