2. Removing ink stains was a problem born with fountain pens
One reason shirts for decades were worn with disposable cuffs was the staining which occurred when using pens. For similar reasons collars too were of celluloid, making them disposable rather than scrubbing them to remove stains induced from hair tonics and perspiration. With the advent of fountain pens, which were also a status symbol, ink stains from pens which leaked or exploded blotted shirts, and removing the ink was a difficult process. Ink stains are still a common reason for the premature disposal of shirts long before they have passed their prime.
The housewife or laundress of the past had a simple solution for removing ink stains, which worked on some other common stains as well. Although it worked best if the ink was still wet, or the stain was still fairly new, immersion in milk for a few hours saw the stain merged with the fluid, after which the shirt was washed normally. Bear in mind that most shirts of days past, at least dress shirts, were of cotton, linen, or another natural fiber, rather than materials of blended man-made fibers, and there was no such thing as permanent ink, which flows from many marker pens today.