On coins etc. the Spanish hexagon mark would contain a letter and a number. Mine is “23” maker unknown? over a “B” (Barcelona).
All hints welcome.
"EVERY COIN IS CLEANED. CLEANING, THEREFORE, IS ALWAYS A MATTER OF DEGREE.
If you send a "dirty" coin into a grading service to be "conserved" and let them do the "conserving" they will charge you for their work CLEANING the coin ..."