Good Morning. I'm new to this wonderful forum, but I don't know how to add my avatar, sorry!.
Andre comments that a letter dated in Benicarló (1805). I can show you this dated on March 20, 1805 and addressed to Agde, treated with 5 disinfection punches and sumerged in vinegar. I do not know if it's the same specimen that Nathan describes in his book.
As you will see, it has:
-Postmark on two lines; "BE / VALENCIA" in black with poor printing.
-French postage "8" centimes on the obverse according to the French rate of 1759 for simple letters passed through Barcelona and Perpignan.
After consulting with Guy Dutau, it could be a disinfection carried out in Spain or through a "Rastel d'Agde", although he is unaware of its use in the French city.
I hope to hear your opinions about this rare disinfection system in Spain? or France?.