Surfactants, Encapsulants, Absorbent Powders and Wicking

Have you ever cleaned a carpet only to have some areas or spots "wick" or reappear? This is usually due to a deeply embedded spot in the carpet backing that works its way to the surface of the face yarn as it dries; much the way a candle wick pulls fuel from the container it sits in.

Often the only way to remove spots that have wicked back up is to re-clean them and even then that doesn't always do the trick. This article by Jim Smith gives some technical background into wicking and ways to stop the spot from reappearing. Have you tried this method? Did it work well?