The use of punch holes to penetrate letters was uncommon in Spain. I have some commercial letters from 1803/05 from a correspondence from Barcelona to Bruges (Flanders). The letter of 1803 was slitted with 2 cuts. The letters of 1804/05 have two, three or four punch holes, probably done with an awl. I'm interested to find out where they were treated.
I have knowlege of the following letters with punch holes related to Spain:
– Bernicarlo to Agde (1803) with 3 to 5 punch holes (mentioned in "Disinfected Mial of Spain" by Nathan)
– Tarragona to Marseille (1804) with 5 punch holes (collection of Denis)
– Mahón to Toulon (1804) with punch holes (collection of Guy Dutau, illustrated in his book on page 369)
– Barcelona to Bruges (1804 and 1805) with 2, 3 or 4 punch holes (collection of André)
– Barcelona to Tarragona (1805) with 8 punch holes (collection of a Spanish collector)
Are there further letters known? Every hint is welcome!