There are ways to restore SOME Details coins to PCGS/NGC problem-free status. I have done it many times, so do not say that it cannot be done. Without giving away any trade secrets, you simply enable/accelerate natural processes. But CAC does not like restored coins, so the only green that you will see is the money from the sales and the envy of other coin dealers.
There is one dealer on Ebay (a former employee of a famous auction firm) who actually discloses his doctoring of raw and certified coins. I had talked him into doing it. His credibility and sales have increased as a result.
Our firm also reveals any conservation of certified coins (we do not sell raw coins), but it does not seem to effect buying decisions in the least, we believe because we deal only in rarities and collectors are happy to find any examples to fill their slots.
Legend and Goldberg may be the only top-tier auction firms who also make such disclosures on a regular basis.