[Edwolf1963]

I agree with all previously - I would leave that one alone. I have had mixed results depending on the card stock and issues that pertained. Glue, pencil - fairly easy. Pen, tar, deeper stains like caramel or oils from CJ - more difficult.

As an example - attached are some backs of low end CJ's (combo of 14's and 15's) recently won. On the left (black background) before, to the right is after. Most of the glue and scrap book paper came out, but as you can see it created paper-loss as well on a couple. Obviously the intent isn't for grade bump as much as just eye-appeal and appreciation of the card as close to original as possible (IMO). Some clearly went well (Hummel), some not so much (Archer) - the Archer was too far gone w/all the glue and scrap book paper from the book it was in. Nothing but water and a Q-Tip. I heat the water as I feel that helps loosen foreign stains/materials better. Some use/recommend distilled water, I've been OK with tap.