If you have a vintage card with a stain or pencil mark, etc and take it out without trimming or the like, is it conservation or alteration?
I think I'm ok with this and kind of agree with pwcc.
Later this month we will publish our Marketplace Tenets which, among other things, touches on the differences between alteration and conservation. Until then, I will summarize why this card is still live in our auction.
In our view, there's a difference between conservation and alteration. Conservation is any act which returns a card closer to its as-manufactured condition and does not render the card artificially different from the as-manufactured state. Removal of dirt, glue, pencil marks, wax, etc. are good examples of conservation, so long as it's done in a way that doesn't affect the natural properties of a card.
Alteration is very different from conservation in that it generally involves the addition of a foreign matter to a card (i.e. recoloring or corner rebuilding) or the removal of material (i.e. trimming, erasing print, etc).
The ‘52 Mantle in question shows no signs of alteration based on these definitions, so it is an acceptable asset to be sold on the marketplace.
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