One of the best and cheapest methods to remove rust from any small part is to use White Vinegar. I use it all the time to clean up old tools, and especially when restoring an old hand saw. I use a large tube with 3 stainless steel wire across the bottom to hold the blade off the bottom. Pour in just enough to cover the blade and let it sit overnight. Use any size container that will allow the part to be submerged. The vinegar is 5% acid and will eat all the rust it come in contact with. The more rust, the longer it will have to soak.
Use rubber glove to handle the part after it has been in the vinegar solution. It will be black and stink like heck. Take it out, shake off the excess, cover the container and head to your scrub place with running water. I use a brass brush as I don't want to destroy the etching on the saw blade but your probably not concerned about that so us any stiff brush you have handy. Scrub away and wash off frequently. will not take any hard scrubbing but could take a lot of it as that black, formerly rust, will just keep showing up. When your done dry the part off and wire wheel it off good to remove any residue that may be left.
The acid in the vinegar will remove the rust down in the puts, cracks and crevices that wire rushing will not get. Your part may have a dark shade to it but a good primer will cover that up. This is a lot more through than just wire brushing it.off. Keep the container covered and it can be used over and over again. It will get to look real nasty and dark but it will keep right on attacking that rust. At some point your going to want to discard the liquid and start fresh but don't get in a hurry to do that. I have done about 10 hand saw blades in my solution and it still is working.
Hope this help some of you that want to get ALL the rust off a part.