I have written about label removal previously and described two possible methods of removing residual glue from polycarbonate bottles. These involved either steam removal or solvent removal.
The surest way is to use a steam gun. The temperature is then high enough to soften the glue and some elements in the glue which are water soluble at high temperatures will be dissolved, although it still will be necessary to use some mechanical action.
Using solvents can be hit-or-miss because there are several types of glue used and although some solvents will work on a wide range of glues there are always exceptions. There is a limitation on the type of solvent that you may use; very strong solvents can get into the polycarbonate polymer and lead to taint problems.
The type of solvent most often recommended is denatured alcohol. Be careful, however, on the choice of product because some denaturants have a very strong taste, such as Bitrex, which is designed to make the taste of the alcohol unpleasant. Also, the higher the alcohol content, the more expensive the product becomes.