Has anyone tried this? I didn't have too much lemon juice or other sources of citric acid on hand so I tried distilled apple vinegar (5% solution) right out of the jug. So far it seems to be working great. I am soaking two back saw blades which were nearly 100% surface rusted (no pitting). The rust has turned to a black, oily goo and is lifting off, exposing bare metal below. So far so good.