It may also help to know that precancels were utilized to speed up mail processing. Precancels are postage stamps that have been canceled before being used on letters or packages. Typically they are stamps cancelled with two lines, and the city and state where they were mailed.
The "perfin" is slang for perforated initials and primarily used by business, large corporations, schools and the like to curtail the theft and private use of postage from their facilities.
ALSO-

to the forum. I hope you stick around a bit. (pun intended)
