I've been using a couple of Rust Erasers on some of my knives and I've had good results.
I'd probably try these before I start using scratchy stuff.
https://www.amazon.com/Rust-Eraser-Sabitoru-Medium-2-piece/dp/B00FS0BFJC
I second the Glock Field Knife. I have one with the sawback.
I read somewhere that it's really a bayonet for a Steyr-Aug or something.
But it's cheap, kind of easy to put an edge on (but keep a stone handy) and if it breaks it breaks.