When I have carpet issues, I first use some Dawn detergent on a microfiber cleaning cloth. When that does not work, I get out my acrylic craft paint, some Q-tips and dot the paint over the stain until it matches the carpet. Use minimal paint and work slowly. With carpet burns, you may have to take manicuring scissors and cut out some of the burned/frayed fibers; then paint. Use blow dryer to dry.