[drcy]

One thing to keep in mind about painting restoration is that the restoration has to be disclosed.

That it is is the "hobby standard" that certain types alterations are not disclosed neither automatically makes it ethical or legal. It could be reasonably argued that shilling is a hobby standard.

As was well said, if a there is nothing wrong or value-changing with a certain type of cleaning, then why is it not disclosed? The answer is because it will change the perceived value in some bidders and buyers minds? Of course an exact same looking card that has not been 'cleaned' will sell for more than one that has-- which is why the cleaning is not disclosed. Whether or not the cleaning or conservation itself is good, prudent and ethical (and in many cases it may be-- I find nothing unethical about removing foreign substances such as glue and scrap paper from a card), that its disclosure will effect sales prices is a reason (including legal) why it has to be disclosed. The ethics and law is alterations and conservation must be disclosed and the buyers and bidders get to decide if and how it effects the value.