What can get rid this adhesive that is on the clear, thin plastic protector of a picture frame (see details)?

You know the plastic that goes over a picture, that protects it.





It had the packaging material glued to it. I can't get the glue off it. It's slightly sticky, a dark brownish yellow color.





I've tried peanutbutter and glass cleaner on it. Did not work.What can get rid this adhesive that is on the clear, thin plastic protector of a picture frame (see details)?
If you put peanut butter on a paper towel and rub the glue with that, it will come off with rubbing over it but not without a little effort. It does work. I use it all the time.What can get rid this adhesive that is on the clear, thin plastic protector of a picture frame (see details)?
Goo be gone
try goo gone
Try toothpaste or mayonnaise, one of them should work.
100% pure silicone spray (hrdwr store), it will melt the adhesive without staining.
rubbing alcohol or baby oil will take it off
Stuff called Goo Gone, available from Target, Wal-Mart and other such places.
rubbing alcohol or lighter fluid