Transparency technique to demonstrate cartilage and skeleton has been used from years 70.This consists basically of the muscle digestion through an enzyme (trypsine), and the staining of cartilage and skeleton using alcian blue and alizarin red on specimens previously fixed to formalin.This technique can be used to study the state of the cartilage and the bones in different stages of the development and to observe abnormalitys.Also it can be used to demonstrate museum specimen skeleton preserved in liquid.In this article is showed the application of this technique for the first time in rodents and adult bats, besides some annotations to optimize the procedure.