A magnet can be used to separate sand from metal. The magnet can be dragged through the sand to take out all of the metal in a certain area of sand. This works by attracting all of the metal onto the magnet, but the sand does not attach to the magnet therefore allowing you to separate the two solids. This could be handy if you want small shards or metal to test the positive and negative sides of a magnet.
This method does not only work with sand you can do it with several other substances as well such as dirt.