Stain removal from cards seems like such a gray area. If you showed me a nice 52 Mantle at auction then showed me an earlier picture of the card that showed tape stains, I'd still have the same level of interest in the card. However, if I saw a picture of the card and saw that it was recolored, re-backed, or had corners or edges rebuilt, then I'd have a problem as it would then be someone else's creation.
If it was a chemical process that could lead to long term damage of the card, I'd be worried. But from what I understand, the process isn't harmful to cards. If someone wants to take the Mantle in this
PWCC listing and remove the stains then sell me the card a few grades higher, I truly wouldn't mind.
I understand everyone has their own opinions on this and some view it as taboo since there is no disclosure in most cases. I'm a big fan of 80s Fleer basketball cards. If I open a wax box and decide to grade a few stickers, before I sell do I need to let someone know that these cards came with wax stuck on them and I had to take it off with panty hose?
SCD did a very informative interview with stain remover Dick Towle that sheds some light on the process. It's worth a read:
http://www.sportscollectorsdigest.co...res/nerattowle