I just dunk mine in hot, soapy water. It should be easy then to peel off the label, or scrub a little bit if you need to.
Goof Off works great on adhesives....just soak the label, let it site a bit and then peal it off.
Krud Kutter for adhesives.
You can also use Goo Gone to get the adhesive off - works great and fast...doesn't really smell good tho.
Peanut butter. You don't have to buy anything special. Everybody has peanut butter on hand. First I take the tip of a pointed knife and score the label then I cover the label with peanut butter. I let it sit overnight on a plate, then take a paper towel and rub it off. Works every time. The nice thing about the peanut butter is it won't run off down the sides like oils do. Hope this helps.