pic 1 is the square in a box from a local auction
pic 2 is the ice cream tub of molasses it spent a month or so in there, scrubbed it with a scotchbrite kitchen scrub pad
pic 3  in the quicky phosphoric acid container for just the square about 20-30 minutes in that, it is a weak solution is like a painter product called metal prep, this happens to be diluted etch & prep by Kwik-kleen
pic 4 is one side after the metal prep, as it dries. the metal prep keeps the metal from flash rusting after being in the molasses

I'd say it looks a heck of a lot better than it did. Nice work!

It is not fast, leaving it alone works but pulling it out and scrubbing helps.
molasses doesn't hurt good wood, if it is rotted it isn't going to help.
pic of other side

I use white vinegar for rust removal, which is pretty cheap in gallon jugs at the grocer's.  Is there some benefit to molasses over vinegar, besides that the tool will taste better?

Bill, heck on a cheap pc of metal, but I think the vinegar eats the metal also, not fast but if you forget!
The other small square that was as bad if not worse that I used naval jelly on. It is now in the molasses where the other one was