Jafe & Fat's,
I don't know if you've noticed, but wire cutters are typically BITCH hard. They laugh at files
A small Dremel stone or sanding disk may be the best bet. I'm going to give my Dremel a go...
Ah yes, I have noticed
I have had some luck going over them several times and switching types of files a few times. The files start to semi bite and will dress the edge. I know its a lot of effort but hey,,,,,,,,,,,,,,,,,,,,don't we all get a kick out of saving a tool despite it not being worth the effort?
I will try a dremel and stone next time.