The sticky residue attracts dust and other dirt particles, appearing in the form of black marks on the carpet.
Wet a cotton towel with plain cold water, wring it out and wipe the stain with wide sweeping strokes. Do not dab! Whilst drying cover the spot with a moist cotton towel.
If the treatment with water is not satisfactory, the stain is most probably caused by some oil or fatty product. Fat and oil stains can be removed by using James Stainspray.
Spray James Stainspray on a cotton cloth and wipe the stain with wide sweeping strokes. Do not dab! Repeat treatment until the stain does not give off anymore dirt.