What to use IN soap to hold label?

[nsmar4211]

Thinking of redoing how I have samples set out. Saw something where someone used metal pins stuck in the sample bar that held the soaps' label, but no information on what kind of metal it was?

Does anyone do this, and if so, what metal is safe to stick in soap?! (HP mostly)

 

[lsg]

Stainless steel or stout wooden tooth picks.