Grommets, or eyelets, are round metal pieces designed to strengthen holes in fabric for the sake of stringing lacing and ties. Though grommets are designed to be used only once and placed in a garment permanently, in some cases it is possible to remove grommets from old clothing and use them in a new sewing project.
Remove the grommet from the old fabric. Use scissors to cut away a small piece of fabric containing the grommet, encircling it and leaving just enough fabric outside the grip of the metal for you to be able to pull with your fingers.
Pry open the grommet. Insert the blade of the craft knife between the edges of the compressed metal on the side of the grommet and carefully pry it open. Move the knife along the perimeter, prying as much of it open in this manner as you can.
Remove bits of fabric still stuck inside the metal. Grip the cloth with the tips of the needle-nosed pliers while holding the grommet firmly between the fingers of your other hand. Tug and twist to remove the cloth bits. Use scissors to cut them into smaller pieces if necessary.
Straighten the compressed metal around the edges of the grommet. Work the tips of the pliers between the curled ends of the metal and pry them open. Grip each side of the metal and bend it outward, moving around the circle of the grommet and restoring it to something like its original shape.
Position the grommet in the new fabric. Cut a hole in the fabric about the size of the hole in the centre of the grommet. Err on the small side; the fabric can stretch. Place the grommet inside the hole.
Close the grommet. Place the fabric, with the grommet, flat on the piece of scrap wood. Hammer the grommet to close the metal edges, gripping the fabric inside them. Flip over the fabric and hammer on the other side, as well.