I'm not sure if anyone else has this problem, but it seems a good portion of the Transformers I pick up from stores have a light greasy film on their blisters and card. For lack of a better term, it isn't the typical "kid grime" some toys encounter. It seems more like residue of some sort from a factory process. I've been trying to determine the safest way to properly clean the packaging without inflicting (too much) damage. Rubbing alcohol seems to do well for the blister, but I have my reservations on using them on the cardboard. Any suggestions or insight to safely clean blisters and cards?