Scrape the edges of the shellac with the back of a butter knife. Work as much out of the carpet fiber as you can. If the stain is still wet, apply paper towels and gently blot as much up as possible. Try not to press down on the paper towels, as that can drive shellac farther into the carpet.
Apply nonacetone nail polish remover to a cloth or towel. Dab the nonacetone nail polish remover along the edges of the stain, gradually working toward the center of the it. Continue to apply nail polish remover until the stained area is covered.
Allow the nonacetone nail polish remover to sit on the stain and work for at least five minutes.
Blot the shellac stain with a cloth or towel. Continue blotting until the towel comes away clean.
Rinse the area with club soda or plain water. The bubbles in club soda help to release stains and to remove cleaning solvents from the carpet fibers.
Blot the area with dry towels until the carpet is as dry as possible. Vacuum the area to fluff the carpet fibers and to remove any dried shellac that fell to the base of the carpet.