The SSK has been my mitt of choice for a few years now. I’ve been through a couple in the past few years, and the cool thing about this mitt is that when you get it, it’s already fairly broken in.
I usually cook my mitts before I use them. There is this stuff that looks like shaving cream. You basically just lather your mitt, and then bake it for a few minutes. It comes out softer than when it went in. My dad used real shaving cream once. It worked ok, but the shaving cream had a green tint to it, so it left a bit of the hue on my mitt. It went away after a while though. Nothing the field dirt couldn’t get rid of.
Anyway, the SSK is oil injected, so I think that’s part of why it is already pretty soft right out of the box.