Place a sheet of polymer clay on a flat surface. The clay sheet should be 2 or 3 inches thick. Cut a rough horseshoe shape from the clay with a utility knife. Use a stencil if it will be easier for you to keep the cut steady.
Pinch the bottom of each end of the arch shape to flatten it and create an oval or circle shape. Wet a finger and run it along all of the edges of your horseshoe. The water softens the clay and allows you to smooth away the rough edges left by the cutting process.
Etch a design in your horseshoe with a toothpick. This can be your initials or even an image. Many horseshoes have branding designs or even the initials of a horse on them, so this will give authenticity to your model. Cut small holes around the arch, centered and spaced about a half-inch apart for the holes used to attach the shoe to the horse.
Place the horseshoe on a cookie sheet lined with aluminum foil and place it in an oven at between 200 and 230 degrees Fahrenheit, depending upon how hot your oven gets. Heat the horseshoe for between 15 and 20 minutes, then remove it and let it cool naturally.
Paint the horseshoe with acrylic paint. Use metallic silver to make the horseshoe look new or paint with brown and gold to give it a used, rusty appearance.