re: Ebonizing

I've used the steel/vinegar before on some red oak and got a deep black that rivaled ebony when shellac was applied.

Recently I needed to de-rust some steel tubing for some gates I'm making. Gallon of 5% white vinegar and water to fill a 4" pvc capped pipe (6' long), slide in the steel and let marinate for a day. 
Steel is super clean and I've enough ebonizing solution for a lifetime!.