Small Pin Holes In US Mint Sheets

I have a number of sheets of US stamps that have small pin holes in the inscription part of the sheet. Is the manufacturing process that causes this? Or something else. How does it affect value? Also is there a term for this. I see it in plate blocks also. Thanks in advance for any information

Can you rule out staples?

Sounds like staple holes, likely done at a PO, rather common occurrence.

hac,
Although you do not specifiy which stamps you have, it was very typical during the mid-20th century to cut the web of nearly-finished stamps into sheets of 400 definitives or 200 commemoratives, then staple them into stacks of 100 through a paperboard pad cover, then cross-cut through the stack to create the 4 pads of final panes for retail sale. Wrap and distribute. Note the staple holes at the right edge of this card from a pad of panes:

it was very typical during the mid-20th century to cut the web of nearly-finished stamps into sheets of 400 definitives or 200 commemoratives, then staple them into stacks of 100 through a paperboard pad cover, then cross-cut through the stack to create the 4 pads of final panes for retail sale.
I'm curious...where did you get this idea from?

(I'm curious because I have about 60 cards, none with staple holes. My colleague has probably several hundred deck cards - none have staple holes. The deck cards I see on ebay - none I see have staple holes. I HIGHLY doubt the BEP stapled the stamp pads. I've ever seen a few complete, shrink-wrapped pads and none had staples).

The importance is to talk specifics.

The card above is from the mid-1970s and speaks for itself.
Panes from this time and earlier tend to have staple holes in the margins. Those from later times do not, which are the pad cover cards typially on ebay..

I've seen plenty of ONE PAIR of holes in MARGIN of USA corner plate blocks, and in some mint sheets, of mid-1970s and earlier.
Curious the original poster didn't specify he/she sees A PAIR OF HOLES in his/her plate blocks. (Why people hold back on some additional clues in their initial posts without pictures, continues to be a long-running mystery.)
"Staple holes" they are.
If I get around to it I might scrounge up some pics to post by and by.