This is a pretty easy instructable, and most of this is well-known. I was just doing my own test and decided to post it here, as it may help someone.
One of the easiest ways to remove rust is using acids.
This 'ible was test to see which under-the-counter acids work best for rust removal.
I purposely did not use regular vinegar, as the standard acidity in vinegar is 4% (though there are several brands with higher).
I had 2 pretty rusty tire chains that I wanted to clean before winter, so I thought this would be a good test, as they were identical items with near-identical rust values.
If you try this at home, you should be wearing rubber gloves. The rusty liquid that this precipitates is very difficult to get off of your hands.
Step 1: Soaking and Rinsing
I put each chain into a separate Ziploc bag, and mixed each bag.
One bag had 1:1 ratio of Heinz apple cider vinegar with 5% acidity and water.
The other bag had 1:1 ratio of lemon juice with 5-6% acidity (does not say on label, but this is an industry standard) and water.
I then put the bags in a bucket to prevent spillage, and waited about a week.
When the bag looks like it is filled with foam or muddy water, it is ready.
I rinsed the chains off in the bathtub, and almost all of the rust came off immediately.
The remaining rust was fairly easy to remove with a wire brush, about 5 minutes on each chain.
The chain with lemon juice had more rust left on that needed to be removed with a wire brush.
Apple cider vinegar had pretty much nothing on it as soon as it was rinsed.
I then hung it outside for a few hours to dry.
APPLE CIDER WINS!!!!!
Side note: The water that you rinse with needs to be dried quickly, i.e. with a fan, blow dryer, or oven, or a thin layer of rust will reform. If this happens, it can easily be scrubbed off though.