Morten
Member
For cleaning pen or sharpie, I bought these: http://www.ebay.co.uk/itm/100x-70-Isopropyl-Alcohol-Swabs-Wipes-Tattoo-Piercing-/230820485153 you are pretty much set for life (or at least a few seasons). Small alcohol swabs, size of a postage stamp, individually wrapped. One is enough to wipe off all my cards after use. I also use them in combination with a rubber to get pencil marks off.