Freeing a stuck zipper can be an absolutely nerve-wrecking endeavour. Repeated failed attempts to loosen the zipper can make you want to throw the offending item in the trash. Don't wave the white flag of surrender just yet, however, because it may be possible to free the zipper with a few simple steps. The problem could be caused by fabric or a thread stuck in the zipper's teeth. If not, the teeth may just need a little extra lubrication in order to slide smoothly.
Rub a sharp pencil over the teeth of the zipper. The graphite from the pencil acts as a lubricant that will allow the zipper to slide more easily.
Inspect the underside of the zipper to see if a piece of fabric or thread is stuck in the teeth. If so, pry the fabric or pull the thread out of the way.
Wiggle the zipper up and down to see which way it moves the most freely. Hold the zipper slider firmly with one hand and grasp the fabric tightly with the other. Twist the slider gently from side to side while pulling it in the direction that moves most freely.
Coat the zipper thoroughly with unscented soap if stuck fabric or thread is not the problem. Open and close the zipper slowly two or three times to distribute the soap evenly.
If the piece of fabric or thread will not budge after lubrication and attempts to work it free, use tweezers to gradually pull the fabric loose. Always zip and unzip items slowly to avoid bending the teeth of the zipper.
Never use any type of oil to free stuck zippers, as this could permanently stain the fabric.