Ancient scientific instruments are to be considered as obsolete objects, which happen to be kept in museums. The function of the objects has undergone a drastic change from a functional use to an untouched situation of rest. Between actual treatments, the objects should not deteriorate in the showcase or the storage room; the museum and storage room environment is a part of the conservation program. Three sorts of threat endanger the object, the environment, human interference, and specific problems resulting from the composition of the object. The climate should be regulated, dust excluded, and humans should be cautious.