These before and after photos were taken during a carpet cleaning performed by Chem-Dry of Tampa FL. The home owner did not know what was spilled to cause the carpet spots. There was no attempt to clean the spots before the carpet cleaning was performed.
The carpet spots were pre treated to help loosen them before they were cleaned. In the before image the lightened areas are the pre treatment. After the carpet cleaning the mystery spots and the pre treatment are extracted leaving the carpet fresh and clean.