Here you go.
http://www.simoniscloth.com/installation/cloth-care-maintenance
"The cloth can also be wiped with a damp (not wet) clean towel. This should only be done after the table has been vacuumed otherwise the dampness may cause the chalk dust to clump together (think of it as adding water to dry clay). Once the dampness has evaporated, a quick brushing is all you will need before playing as moisture will cause the fibers in the cloth to stand up and a quick brushing will smooth things out.
Stains on the cloth? Contact your local Dry Cleaners as they have some pretty interesting and effective techniques to resolve these incidents. Remember, Simonis is a worsted wool, so be sure to mention that fact."