Simple Ways to Get Glue Off of Plastic: 11 Steps (with Pictures) - wikiHow For glue left by a label on 1 plastic jar, for example, 1 tablespoon (15 ml) of baking soda and 1 tablespoon (15 ml) of oil should work. What Type of Oil to Use If you want your plastic to smell nice, mix a few drops of essential oil into your mixture, along with the cooking oil. Choose one like peppermint, lavender, or lemon.