Pretty much anything wrapped in foil can work as a stylus. A pencil or pen wrapped in foil is probably the simplest example. Just tear off a piece of foil that is about 3-4 inches long. Then roll it onto the pencil leaving about an inch of foil sticking out past the eraser. When it is rolled up, fold this extra bit of foil over the end. Then fold up any sharp ends. To finish smoothing the end, you may want to press it against a table on all sides to ensure that the end is flat and free of any sharp edges. The creased foil should hold itself in place, but if you use tape to secure the foil, make sure that there is enough exposed foil to make a good contact with your hand. If the stylus is not very responsive, you may wish to adjust the shape of the tip by either pressing it into a different shape or rerolling it.