You can find details on various methods of marking accession numbers here: http://www.collectionstrust.org.uk/collections-link/collections-management/collections-skills/item/926-labelling-and-marking-museum-objects-booklet.
The methods worked for us in stores with a variety of environments. Occasionally varnished accession numbers stuck to acrylic shelves, on display. It is likely that, in these cases, the accession number had been very recently marked, and that the temperature in the cases was elevated by the lighting. Hope this helps. Vivien Chapman (retired from National Museums Liverpool) ****** Unsubscribe by sending a message to [email protected] Archives through August 2016 at http://cool.conservation-us.org/byform/mailing-lists/cdl/ Archives from September 2016 onward at https://www.mail-archive.com/[email protected]/
