Button Safety Pin
I got asked a question, so here is a Button Pin, aka Button Safety Pin. So, you can use these instead of sewing on precious buttons that you need to take off for cleaning. The little dent makes it easier to push through the material, catch the shank of the button--the buttons have to have shanks--and then go back into the material. These are a 3/4ths of an inch long.
Of course, you have to get the hang of them, but you can see why they would be handy on something that you don’t wear open. Any glass or metal buttons are better off not going through the cleaners, and even when they say, they can be cleaned, I avoid it unless it is hand washing.
I end up using them for knitting markers too. They work for knitting because they don’t have the looped portion at the closed end; safety pins with the loops would get stuck on the yarn or thread, so don’t use those.
I get mine from Wawak via their website. They have a big, honking catalog that has lots of stuff, although some of it is clearly for businesses rather than home dressmakers.
Go here: https://www.wawak.com/Cutting-Measuring/Pins/steel-button-safety-pins-00-34-10pack/?sku=SP4003