Just soaked two farrier rasps I was gifted, they were used and a little bit rusty and clogged with horse hooves material. They now look like new and are fairly sharp. I soaked them over night in vinegar. While they were soaking, you could see bubbles drifting up off them for hours, even the next day bubbles were still rising. There was so much rust laying in the bottom of my little foil pan this morning, I was amazed. All the rust is gone. I wonder if taking a wooden or rubber block and using 320 grit sand paper and just running the block down the rasp, in the direction of the sharp edge, if that would just touch up the edges a bit, shouldn't take much to clean up the edge. Might give it a try on one of them tomorrow, cause I'm a redneck:)
Here is my little aluminum foil tray, had a slight leak at first but got it sealed:)