I,ve never tried them on Mandolin and banjo as as far as I am aware it's only the "wound" strings that have the coating - and on the 5 string banjo the only wound string I have is the 4th maybe if they sold single strings?

maybe they'll bring out a skin tight gortex glove to save string wear - they already sell elixir/gortex dental floss (I was sent some when I bought my last sets of strings)however that doesn't last any longer than the standard stuff!