I had a cap on, so couldn't wear my Frogskins on top of my head indoors like usual, so I hung it on my t-shirt. When I took it out, one stem came off and I saw the hinge screw was missing. I retraced my steps and couldn't find it. It could have gotten stuck in someone's shoe. Is there a specific name for this type of screw? Any chance I'll be able to get a replacement at the hardware store, or do I have to take a chance and buy one of those drug store glasses repair kits and hope a screw that fits comes with the kit?