Steam clean the top of the rug. If the fibers do not fluff with steam cleaning, consider replacing the rug entirely. Measure the rug length and width, and go to a home furnishing store to find a new rug that fits the area and matches the room decor.
Salvage the rug if possible. If it can be salvaged by replacing the rubber backing, measure the back of the rug and purchase a rubber backing slip from a carpet store. Purchase a backing slip the same size or slightly smaller than your rug.
Flip the rug over. Confirm that the rubber backing fits.
Apply a layer of hot glue from the glue gun along the edges of the rubber backing. Place it on the back of the rug and press down on the glue. Allow it to harden and dry.
Replace the rug to its area.