Riding in wet weather or dusty condition can cause some havoc with the zipper on you leather. Before you start cruising all over town or shelling out cash try a bar of soap. Run the edge of the soap up and down both sides of the zipper and then work the zipper up and down. This helps lubricate the zipper up and does leave a undesired residue.

 

jp tech , soap works great . I have also tried a shot of WD40 and it helps free up the sticky zippers on my work uniforms .

 

I rub the zippers with a wax candle then run the slide up and down a few times. Lubes them for a long time.

 

I use "zipper-ease" zipper lubricant you can get it at any dive shop, use on wet and dry suits. goggle it or any local dive shop should have it...Made for just that zippers, metal or plastic!