Thread a sewing needle with the end of the snag. If the snag is a loop, cut it in half to create two loose threads and fix each separately by threading them onto the needle one at a time.
Poke the needle down into the fabric as closely to the base of the snag as possible.
Push the needle halfway into the fabric and push the point up out of the fabric about 1 inch away from the base.
Hold your finger over the needle's exit hole and push the needle slowly out. Use your finger to apply pressure and let the thread slip out of the needle, leaving it on the inside of the upholstery.
Apply a thin layer of liquid fray preventer over the base of the snag and the needle's exit hole.