Glass can have weird problems with moisture, it's like the silicon leaches out, leaving what looks like white soap residue. This is accelerated if the sheets of glass are stored together with no dividers.
I find this most often when glass is stacked flat.
At my shop I have a stand-up area next to each workbench, about six inches across. I stand up the sheets of glass, and if they don't have plastic sheeting or plastic bags between each sheet of glass I'll put a piece of cardboard between each sheet.
Six inches wide, 25 inches deep (for a couple of wide-body sheets mixed in) could store 20+ sheets of glass. I store it on edge 'the tall way'.
The bottom of these glass storage areas is wood. I don't want to set glass into the bin too hard on a metal or stone surface.
Glass is heavy! Expensive to ship! So I generally buy 10-20 sheets in bulk when I visit Marco. This never becomes more than what the little areas next to the benches will hold, so I've never needed a LOT of glass storage.
My first pinball job had this arrangement... to the right side of every person's pinball bench was an area to put the machine's glass and backglass, and to store sheets of fresh glass. It's an arrangement that serves the workflow of a pinball bench pretty well.