A nontoxic way to remove the sticky residue left by jar labels and other stickers is to rub the area with vegetable shortening and let it set for a few minutes. Then use a scraper or the dull edge of a knife to remove the majority. Next, wash it in soapy water and if it all doesn't come off, repeat the process. A couple of times should do it. This glue-remover process will work on plastic as well as glass.