Recently I acquired an older pair of Mountain Horse dress boots, and the zippers were a little sticky. (They weren’t literally sticky, but they didn’t pull smoothly.) At one point, I had a stick of Zipper-Ease which I bought from Dover, but to be honest, I just couldn’t handle the smell, so I tossed it out. A listing for beeswax on ebay suggested that it could be used for lubricating zippers, so I thought, Hmmm, Passier Lederbalsam has beeswax in it. I ran the zippers down to the base of the heel and put just a bit of lederbalsam on each side of the zipper from top to bottom. Voila! It worked! Doesn’t solve world hunger, but it sure made my day easier! 
I have also used chapstick (a tube bought just for this purpose) and a very precise amount of clipper blade oil.
Good to know!
Like both these ideas…but does the dirt collect on the zipper more if you have this stuff on them?
How about just a simple squirt of that ever ready WD-40…lube for all hard to turn nuts and bolts.
Wd 40 is great and I do like that smell!
I’m not sure if it causes more gunk to accumulate on the zippers. My guess would be that just like with leather tack, the zippers will need to be cleaned and re-lubricated every so often. If anyone has any suggestions, I’d love to hear them!
Chapstick, clipper oil, and WD-40 sound great, too! It’s nice to have options!
Take a #2 pencil and rub it up and down the closed zipper. Then work the zipper a few times. Graphite is great for this use because it does not gunk up the teeth or attract more dirt.
I use the Berts Bees beeswax lip balm. I wipe off the excess and haven’t noticed any gunk build up.
[QUOTE=keysfins;8884295]
Take a #2 pencil and rub it up and down the closed zipper. Then work the zipper a few times. Graphite is great for this use because it does not gunk up the teeth or attract more dirt.[/QUOTE]
Second this.
Pharmaka Hypofekt works really well, too - and the applicator nozzle/straw combo is perfect for zippers. It’s designed specifically to clean and lubricate zippers in footwear.
I’ve never noticed a build up of any kind after using it.
Old Navy Standby for Sticky Zippers: bar soap.
It does not leave any residue as any sort of oil based product will. It does not require periodic cleaning as oil based products will. The major downside is that it must be applied more frequently, sometimes every time you use the item. That’s a pain but maybe less of one than cleaning oily messes in the small context of zipper teeth.
I’ve never tried liquid soap. I’m not sure it would work.
That part about oily buildup is really important. An analogous problem is the sticky key problem in a lock. There the most efficient answer is graphite, a dry product. No reputable locksmith would likely suggest penetrating oil or any other like substance. The suggesting of the number 2 pencil is suggesting graphite.
Cheap, easy, and as you use the zipper it will work better and the “lubricant” will no longer be required. And there’s no mess to clean up!!! 
G.
We used the parrafin wax removed from the jars of homemade jelly. The wax is sold in stores. We always had some around the various family homes because everyone made jams and jellies.
I have always heard to use a pencil or a candle (similar to the paraffin wax) for sticky zippers. Recently I saw someone recommend a crayon - use the same color as the zipper!
I might try the oilier options in a dire emergency, but would try to stick with something less likely to grab dirt/grime if I had a choice.
Thank you all - these are all great suggestions, and low cost! G., I appreciate your explanation, too, as it always helps to know why things work. I will be trying some of these in the future.
[QUOTE=keysfins;8884295]
Take a #2 pencil and rub it up and down the closed zipper. Then work the zipper a few times. Graphite is great for this use because it does not gunk up the teeth or attract more dirt.[/QUOTE]
Instead of using a #2 pencil, you can go to places that cut keys. They usually have a tube of powder graphite to use for locks with sticky tumblers. You just “puff” it out of the tube.
Just be careful not to puff out too much!
I had a shoe repair person tell me to use the silicon waterproofing spray for the zipper. It does have a very strong smell, but it does a great job and isn’t greasy and doesn’t seem to attract more dirt or build up gunk over time. He advised this after doing a boot zipper repair for a friends boot. so far so good.
