A screw is a fastener that has an external thread that is wrapped around a cylinder. Some threads are designed to be joined with a matching thread, called an internal thread. Screws come in every shape and size imaginable. As a result one tool will not work for all screw types. Some may take flat-head screwdrivers, some Phillips head, other hexagonal tools or Allen wrenches. Generally the smaller the screw that harder it is to work with, but even these can be fastened and removed without too much difficulty.
Determine the style screw and locate or purchase the appropriate screwdriver. For extra-small screwdrivers a good place to shop is a computer or eyeglass store.
Place the object securely on a flat surface to work on it. If possible put a piece of fabric or carpet under the object to catch any small screws that may drop during removal.
Insert the head of the screwdriver into the head of the screw and turn in a counterclockwise motion. Tiny screws are easy to lose so work slowly and carefully.
Place removed tiny screw into a small container for safe keeping.