Stuck zip

[Tengu]

Its a plastic teeth with metal slider one.

How do I get it unstuck?

And stay so?

 

[Nice65]

Silicone spray works well for keeping them smooth. But I'm not sure what to advise for releasing it.

 

[Giantwalks]

Plastic teeth and metal slider you should try with cooling down with a lighter-gas-refiller to loosen because the plastic will shrink quicker than the metal. That should work. For maintenance you can use almost everything depending on the material of the bag/trouser/satchel whatever. If the material is fragile I would use Greenland-Wax or bee-wax or just a candle except tallow-candles.

 

[Seagull]

Providing you haven't broken off the little tag and there are no bits of of thread or material clogging the mechanism, try gentle pulls whilst holding the zip below the place where the gathering slide is .
I have freed these same type of zipper, with just a few ice-cubes to cool things a bit.

Once clear, keep the track pieces lubricated by rubbing their whole length (and the back ,as well as the front) using a 2B, or softer pencil.

Best of luck
Ceeg

 

[santaman2000]

Dish soap (fairy liquid)