Recovery and enhancement of faded cleared and double stained specimens

Cleared and stained specimens may become faded and/or opaque after long per iods in preservative solutions. We developed a technique to revitalize fade d and/or destained specimens regardless of their age. By adapting and revis ing Wassersug's procedure for differential staining of bone and cartilage, we successfully cleared and restained numerous small amphibian specimens of various ages, After rehydrating, specimens were bleached in potassium hydr oxide and hydrogen peroxide, stained with alcian blue, and macerated with t rypsin as needed. Alizarin red stain was applied or reapplied, although sta ining occasionally was unsuccessful in old formalin fixed specimens. After restaining, the specimens were dehydrated and placed in glycerol.