How to repair a broken zip on a piece of clothing, other than replacing it?

Question:The problem is that the two sides of the shirt won't tie together when you pull the zip upwards.

Answers:
Before you decide to replace a zipper, examine it carefully to see if you can repair it. If a tooth is missing in the upper two-thirds of the zipper's tracks, the zipper should be replaced. If a tooth is missing near the bottom of one of the tracks, zip up the zipper so that the slider is above the damage. Thread a needle and make several stitches around both rows of teeth, just above the missing tooth, to make a new stop for the slider. Stitch over the new stop several times to make sure it's firm.

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