"Non Wire Hangers"
"Wooden hangers were created with a specific purpose in mind. The specific type of wood used in most hangers is hand-selected to repel moths and other unwanted insects and pests that can harm clothing. The wood in the hanger helps make sure that clothes are not only unwrinkled, but that they stay undamaged while they are hanging out in closets."
https://www.amazon.com/Panef-Corp-Powdered-Graphite-Lubricant/dp/B0016GZQ60
Now I don't use hairpins but I would think the side WITHOUT the sharp pointed end would be better against your scalp?