Sugar (or salt as was also proposed on this thread) are quite self evidently not a solution to be used in these products which contain water.
Here's an example product:
http://www.origins.com/product/3829/10219/Bath-Body/Star-Col...
Couple that with the added benefit of being water soluble, cleanup after using the product is especially easy. Scrub and rinse (and gently scrub) until you can't feel the product. It's self-documenting. :-)
http://www.treehugger.com/organic-beauty/8-homemade-salt-and...