I just watched the section where you took the screenshot from. It is an isopropyl alcohol pen. You can get them as CD writing eraser pens. You can just buy bottles of isopropyl alcohol if you want to use it to remove things.
CAUTION: It removes printing on the paper stickers!
Hope this helps!
-plarnold
CAUTION: It removes printing on the paper stickers!
Hope this helps!
-plarnold