Anyone ever try Rustoleum rust converter?

I've used this product for repainting wrought iron. You brush it on & it converts red rust to black rust. (At least, I think that's what it's doing--it converts the red rust to something matte black that you can paint over).

IIRC Charlie used black rust as a finish on one of his razors and it looked great. He boiled it to convert red to black. The rust converter looks like it achieves the same thing without the boiling (I'm a little squeamish about heating hardened steel). I'm thinking, clean the steel, then dip in a saturated solution of vinegar, peroxide, and salt. Once the blade is covered in a uniform coat of red rust, brush on the rust converter.