Question: What is the best way to clean Travertine?

Answer: Travertine can be washed with fiber brushes, mild soap or detergent, and water. In extreme cases, Travertine can be cleaned with a light spray of a pressure washer. In this case, the Travertine may need to be resealed. 

DuPont™ StoneTech® also makes an excellent Travertine cleaner (Click to buy: http://amzn.to/1gByW5E).

For tough stains, use a poultice - such as Miracle Sealants Poultice (Click to buy: http://amzn.to/1gBwqw3)