First, apply a spotting gel that is formulated for tar removal and safe to use on carpet. This treatment keeps both solvent and discoloration from running to the base of the carpet. If the tar is heavily caked, you may need to carefully snip the tip of the fibers with duckbill scissors prior to treatment. Agitate gel slightly. Allow it to dwell as required on the product label.
Next, blot with white ... — Gary Clipperton, ProClean College, (719) 598-5112