PCGS Restoration Service

Yes, and they always have. But there was a time when they did not advertise these services like they do today. In the early days of the TPGs you had to specifically ask them if they would do it for you. And back then, many, probably even the majority of collectors, were not aware they would clean coins for you.

No. And that's perfectly logical and understandable because there are way too many times that whatever you are asking to have removed from the coin is covering up something that could not be seen until was removed.

For example, if a coin is darkly/heavily toned and you have them remove it, excessive hairlines and or scratches could be revealed underneath that toning that previously could not be seen thus rendering the coin a problem coin that cannot be given a clean grade.