Sand dollars are marine animals belonging to the Phylum Echinodermata, class Echinoidea, and order Clypeasteroida. They are related to sea urchins and starfish. They got their name from their appearance. They possess flattened, disk-shaped shells, which lie below their thin skin. They are generally about three inches in size. When sand dollars are alive, their colors can vary from gray to red and purple to black. Live sand dollars are not commonly seen, but their tests are found often lying on the beach. Their shells are gray to white in color and have a five-petal flower pattern in them. Sand dollars are found in areas from Alaska to Northern Baja California. They live on sandy shores in the low intertidal and subtidal zones. They are also found in deeper seas. Sand dollars are also called sea cookies, snapper biscuits, sand cakes, cake urchins or pansy shells. They are used to make various interesting craft projects and decorations due to their beautiful shapes and patterns. They can be used as picture enhancements in home, corridors, patios, and also as Christmas tree adorns. There are several known methods for cleaning sand dollars. Mentioned below are some simple steps to clean them. Soak in Several Changes of Water The first step is to prepare the bucket or container where the sand dollars are to be soaked. You can pad your bucket or container with a rag or paper towel to provide protection to the shells. Now soak the shells in the bucket or container of fresh water. Avoid placing the sand dollars one on top of the other as this might cause the shells to fracture due to their weight. Instead stack them on their sides in your bucket. After sometime, the water will turn to a brownish color due to the dirt and sand build up in them, and may become smelly too. So the sand dollars should be soaked in several changes of water until the water becomes fairly clear and odorless. Treat them with Bleach Next, soak the sand dollars in a mixture of one-fourth part bleach to three-fourth part water in a bucket to kill off any dead tissue that might be there. The bleach also helps to make the shells whiter. Allow them to remain in that condition for about one hour. Avoid using too much of bleach or leaving them longer in the bleached solution as this will make the sand dollars brittle. A toothpick can be used to scrape off the dead tissues if they are still retained. Rinse with Fresh Water Now rinse the bleached sand dollars in fresh water a number of times until the bleach gets neutralized. In case the sand dollars are not as white as you would desire, then again place the sand dollars in a bleach solution. However, the sand dollars will become more brittle with each bleach treatment. Allow To Dry Following this, place the sand dollars on a flat surface and let them dry out in the sun. The longer the sand dollars are in the sun, the whiter they will become. If you are not able to naturally dry them, you can wipe them off with a paper towel and place them outside and allow to dry in the air. Preserve Them Once they have dried, you can place them in a wax paper and coat them with a mixture of equal parts of water and Elmer's glue or any white glue on one side. Allow them to dry. Then coat the other side with the mixture and dry them. This is done for protection and hardening of the shells. So, the beautiful sand dollars are ready now.