I Cryo treat all my edged tools
Cryo-treating metal is a method employed to remove retained austenite and untempered martensite from the microstructure. It doesn't actually remove it - it transforms it to a more stable, less brittle form. Just a little tip from your friendly neighborhood heat-treater! We usually do that anywhere from -150*F to -300*F but in this case, if you've access to a deep freeze, that should work well enough.