Another (safer) way to remove the zinc plating - I just finished 3 eastern white pine tool boxes to hold molding planes. I thought about going the high-quality hardware route, but decided it didn't make sense to spend $120 on each tool box for brass chest lifts and hinges, or $300 each blacksmith-made iron strap hinges and locks.
So I nosed around my local Lowes, and found some elcheapo steel chest lifts, hinges, and hasps. All were zinc plated, in in my view, are really ugly, so I stripped the zinc off of the hardware and fasterners with citric acid. You can get citric in solid form from any home brewery supply store, and some old-school pharmacies. It's safe to work with - even in concetrated form, the pKa of the acid is high enough that it will not burn your skin.
Add about 2 teaspoons to about a pint of warm tap water (it should all dissolve easily), dump the zinc-plated stuff in it, and leave it for about an hour. You'll see a lot of gass bubbles coming off (that's hydrogen, by the way). Then remove the hardware and rinse clean in tap water. If not all of the zinc came off, you may need to use more citric in the mix or re-treat it.
This also works extremely well for removing rust on old tools - the citric acid will not damage japaning, nor will it attact iron, cast iron, or steel - just the rust. In this case, the reaction is slower, so the tools should be left in the bath for 4-6 hours, or as long as 24.
By the way - Home Depot (at least in my area) still sells straight-slotted wood screws in small packages, though they are all zinc-plated.