Vacuum the carpet with a crevice tool to get rid of loose soil.
Mix a solution of hot water and a few drops of dish soap into a bucket. Scrub the soapy water onto the soiled carpet with a scrub brush. Continue scrubbing, rinsing out the brush often in the soapy water, until soil no longer comes off the carpet.
Rinse the carpeting with a rag and clean water. Blot thoroughly with a clean rag to remove excess moisture.
Spray a degreasing carpet cleaner directly onto the remaining soil spots. Wait five minutes, then blot the cleaner from the carpet with a dry rag. Repeat as necessary until all of the soil is gone.