http://www.evaporust.com/
Just wanted to put up a little feedback on this stuff. Surprisingly enough it actually works. It does require some scrubbing here and there to speed things along, but overall I am pretty impressed. No noxious fumes, heavy rubber gloves, explosive byproducts, or risk of electrocution.
I am going through rehab on a couple of #6 planes ( 1 family heirloom, and one from ebay). Both of these planes are rusty to the point that screws were seized and prospects of beauty were questionable. See attached image of the ebay plane. The heirloom was actually worse having spent about 15 years on my grandfathers back porch.
It isn't magic, it isn't fast, but it does work. Within the process of the day I was able to go through all of the small parts, frogs, and irons. The first body is soaking over night, but after only a couple hours it was looking good. I found that taking the parts out and scrubbing or wire wheel cleaning them worked wonders for getting to even thick rust deposits. I don't know if the thicker deposits would dissolve on their own, but I kind of doubt it.
I will post a follow up once my camera gets back from vacation. The irons and lever cap pictured all came out looking very nice, the iron actually turned out the be a sweetheart. Never can tell what you will get off ebay when you bid on ugly ducklings