Posted By:
Bottom of the NinthPower erasing is a mechanism to make cards appear better centered by removing part of the image to equalize the appearance of the borders. It is done using an electric power erasure and is different than using an art gum erasure to remove stray pencil marks.
As to removing stuff on cards that was not supposed to be there in the first place, like glue, ink and pencil...if it can be done without detection and without chemicals, why not? There are many types of ink that cannot be removed without using a professional restoration service.
I think you need to give the grading companies a break and trust that they (except for PSA based on the board consensus) put the cards through enough of an examination to determine if the cards have been altered. If you don't and have either lost confidence or never had any to begin with, then stay away from graded cards. I think they are more capable, certainly those at SGC and Mike Baker at GAI, than they are given credit for. Not sure I see the incentive for them to consciously holder a card that they even suspect might be altered. They make more money rejecting it and making the submitter try again (if he feels the card is worthy of grading) and absolve themselves of a potential liability.