re: liberty stamps w/perfins vertical streaks picture
being posted in the newcomer corner.....
I will add, perfin is short for perforated initials. Commercial businesses, municipalities and other entities would punch their initials into their stock of stamps for theft deterrence.
re: liberty stamps w/perfins vertical streaks picture
The "vertical streaks" are most likely impressions from a roller cancelling device, commonly used on parcels. They provide evidence "proper" postal use rather as opposed to philatelic use.