Why should specimens not be stored inside the cryostat? FAQ Report The cold air inside a cryostat is very dry and will rapidly dehydrate the specimen. Specimens may be stored during the day when the automatic defrost cycle is not activated but they must be covered by a layer of cryocompound or wrapped in aluminum foil to prevent dehydration. Not only is the specimen dehydrated, but also the cryocompound surrounding the specimen. The cryocompound sectioning properties are negatively influenced (feels like sectioning chewing gum). When sectioning of a specimen is completed, remove the remaining sample from the specimen holder while still frozen and wrap in a double layer of aluminum foil, label and store in a sealed container in a -80 °C freezer.