My husband and I have had metal salt and pepper shakers similar to these for a long time.
The main difference is ours are metal and you can’t see through them. I have written on them with paint pens, sharpies and it always wears off.
After a duh moment when I was cutting out a stencil (for a project you will see soon) I decided to cut out stickers for the shakers in permanent vinyl stickers for them!
As soon as the shakers are dry I will put them on. hopefully it will last longer than any other labeling method, I am tired of guessing. pepper doesn’t go well in most of my baking! LOL!!!