I have always left my safety pins open and stored them in one of my old medicine containers. I have four different containers for four sizes. I left them open because it was less trouble than to open and close them every time I needed them.
Well, I picked up a box of 250 pins for 50 cents at a garage sale. They were closed pins and a closed package, however when I opened the pins they had a small rust spot on the tip where it touched the top. I threw away a couple because I couldn't get it to go through my material. I got out a new metal scouring pad, and I raked the pin across the pad a few times. I was able to get it to go through 6 layers of thin material...... Yep, I swished all of the pins back and forth, left them open, and stored them in a container.
Syl