I discovered a few trick years ago that has repeatedly helped me find? dropped objects.
Watch it fall, if possible.? Things often bounce oddly and if you keep your eye on it, you might see where it bounces.
Failing No. 1, if it's something not too dear and you have more of the same, drop another and watch where that one goes.? It's amazing how often identical items bounce the same direction.
When neither No. 1 nor No. 2 apply, dim the lights, get down on the floor, and shine a flashlight at floor level in various directions.? Small thing will thus cast large shadows.? Often works well.? Really shows you how much you needed to sweep the shop...
