Project Farm did a test of some common rust removers.
https://www.youtube.com/watch?v=6-MC_ZEXQbwTL;DW:
Best out of the tested products seems to be Muriatic Acid, Krud Kutter, Evapo Rust, Naval Jelly, and white vinegar, in that order.
Muriatic acid seems to work well if the item is durable, but it can cause etching, eats away non-metal bits, and doesn't protect item long term. Naval Jelly seems to be the choice for when you need something that won't flow. CLR & Coca-Cola were deemed useless or not worth bothering with.
He didn't test phosphoric acid (except for the small amount in Coca Cola).