If you are having a hard time removing the labels of your jars or there is still some glue that you cannot take away, use this mix which is totally natural and made from ingredients that you probably already in your kitchen.
1 spoon of Baking Soda
1 spoon of Vegetable Oil
Mix both ingredients until a paste is created,add the paste into the jar where the glue or label remains and leave it for 1 hr. After one hour take off the paste with a sponge and wash the jar with water.
I hope this magic mix works for you, for me it did wonders and left my glass jars very clean.