When a screw goes missing from your glasses, you lose either a lens or the earpiece. In a pinch, you can replace that missing screw with a toothpick.
Picture: liz west
If your glasses lose a screw and you don't have an eyeglass repair kit handy, a toothpick makes for a handy temporary fix. Line up the holes and poke a toothpick in as far as it will go. Break the toothpick off and seal it with a piece of tape. This should hold your glasses together until you can get a replacement screw or drop by your favourite glasses vendor and have them fixed.