Loosen Up Stuck Zippers
No situation can come up worst rather than you waking up late and the finding that your bag, shoes or even your brand new sweater has got a stuck zipper on it. You might want to try tugging on it, but there is a chance that you might end up breaking it. WD-40 is the solution.
source: science101.com
Spray it lightly on the zipper teeth, work it up and down, rub-off the excess substance and you’re good to go. If you want to avoid getting WD-40 on the fabric, spray it on a lid, and then apply it on the surface with a brush. The best thing is that it works for all kinds of zippers because of the petroleum inside of the product.