Tiger salamander (Ambystoma tigrinum), cleared and stained specimen. Clearing and staining, also known as diaphonization, is a process used to reveal internal structure. The specimen is treated with alizarin dye to reveal the bones (green) and alcian dye to reveal the cartilage (red). It is then treated with an enzyme (trypsin) which removes most of the tissue leaving behind collagen. The specimen is then stored in glycerine.