I can't say I've really come across these clips here other than a few pristine ones I was given a while ago.
I decided to try rusting the ones I have.
I read somewhere they can be sanded, dunked in vinegar, then put in contact with an already rusty item and set out in the air to 'cook'
And it worked!! literally within hours!
I like the shape of the ones from Nathalie better but as far as the rusting process goes, I'm thrilled!
now I just need to make something to hang on them!