Evaporust, like many of the others have said. There's a quicker equivalent, that I believe is also cheaper, Youtube channel "Project Farm" found when testing de-rusting agents. Not trying to shill for the channel, I just like watching his videos and testing methods seem to be mostly sound, and in the interest of full disclosure, I am neither a subscriber to his channel, nor a contributor, I just watch him on a regular basis (which probably bumps up his stats and increases his ad revenue a bit).
I, personally, have been using Evaporust for a while and like it. I have left parts in for over a week with no damage other than what was caused by the rust. Keep in mind, Evaporust removes the rust, it does not "convert" it back to good metal, so you will have pitting if the parts have been rusting for a while. I have also not found it to be very "paint safe". I.e. just about everything I put into ER that still has paint on it, the paint gets soft and loose, although it is NOT a paint remover except in small patches. I know that may sound contradictory, but I have had small paint areas just fall way but other areas get soft, but still took some work to fully remove, unlike paint removers I have used, but even after the paint has re-dried after being immersed in ER, its easier to remove when comparing to other parts, from the same machine, with the same paint on it that did not go into the ER. Not an issue for what you're doing, but something to keep in mind for later. Don't forget, ER (or its competitor's equivalent products) is expensive, but its also re-useable. I don't worry about mixing new and old (I don't have any "new" anymore at this point anyway), just keeping the containers sealed to minimize evaporation losses (since its water based, you can add water to ER if you see some of it has evaporated while in storage, the active ingredients are left behind, only the water evaporates off).
I think you'll be fine with the rasp, the issue may be the taps and die. Depending on how badly rusted they are, they may be too dull to be useful anymore. Dull taps are prone to breaking, leaving you with a potential huge headache in trying to remove it. Not sure about dies, but taps can be sharpened, but what it costs if you were to take it to a professional, I have no idea and if its even worth it. If you know a hobbiest metalworker with a TCG, perhaps they can sharpen them for a reasonable fee. Then keep that person in mind for when you need router bits sharpened.