I follow a number of machine / tool restorers on Youtube as I’ve been getting into tool restoration myself. Had been using vinegar baths to remove rust, but I’ve seen most of the restorers I follow have switched to Evapo-Rust exclusively. Seems to work really well.
Right now you can get a gallon jug of evapo-rust on Amazon for a little more than $19usd but you can get an additional 25% off using the discount code 25fitzall at checkout. (Fitzall is a podcast by Jimmy Diresta and a couple of other guys). Only valid for Amazon US, only for the gallon (128oz) size and I’m not sure how long the discount is valid for. I just bought a gallon myself last night.