Glad you asked...
Mix up some bleach and water in a bowl. Put in the sand dollar and let them soak for about 10 minutes. Do not let them set any longer because they will start to crumble. Rinse the sand dollars in cold water and then let them dry. Use the following link for step by step instructions on how to bleach a sand dollar. http://www.squidoo.com/TheSanddollar...
Then again, this answer might help you...
You clean it in regular water and let it dry in the sun, Generally the drop them in a bleach solution (bleach and water.)for 5 minutes. .

