There are diverse considerations that archives, libraries and information units that hold cultural heritage collections should formulate before using identification labels. Labeling is essential when classifying bibliographical material and it involves some difficulty due to adhesion and visibility requirements. When facing books with historical or heritage value, the addition of external elements on the cover or spine can be considered as an invasive treatment, either in terms of its materiality or from a aesthetic point o view. In the following text some problems posed by this issue at the Archivo Central Andres Bello are reported, where diverse proposals have been studied and compiled, aiming at reaching an appropriate implementation of conservation labels.