If you look for safety pins at OfficeMush, you will fail. If you repeat the exercise at Home Despot, you will be laughed at.
What, I ask, was so wrong with either of these ideas? Safety pins are hardware, in the classic sense -- "metal goods and utensils." The kinship between pins, nails, picture hooks, and screws is close, or so it seems to me. But I could find only the latter three in a hardware store.
Equally well, my mind classifies safety pins together with staples and paper clips, both staple goods of an office supply store. They're small metallic objects you use to hold stuff together. I also think of them, perhaps, as akin to art supplies, like glue, construction paper, and clothespins, all of which I also saw at OfficeMax. But no safety pins.
There's no need to go into the details of my searches through kitchen supplies and baby essentials (does no one use cloth diapers any more?), but I did eventually find safety pins in a drug store, under "closet supplies." Of course. They were between spools of thread and clothes hangers.
The sewing connection makes sense. I was going to try a crafts store next. But I will never really be able to wrap my mind around various accidents of the American system of classifying consumer items, both across stores and within. The dividing line between supermarkets and drug stores, for example, remains obscure to me, as does the juxtaposition of spices with coffee and tea. On the other hand, the consistent segregation of canned soup from canned vegetables from canned fruit from pasta sauce leaves me baffled every time.
I'm sure there's a reason; I'm equally sure I'll never really understand it.