We recently got told about CRC Evaporust, which is supposed to be fantastic for cleaning off rust, so Son 2 got some & we tried it on some old tools, that had a certain amount of rust on them.
Impressed!
Here are before & after shots, & it even cleaned out the bottom of the tub that I used to de-rust things using vinegar a while back!
That was after ~48 hours, Thursday morning > Saturday morning, but they were already pretty good on Thursday arvo & Friday morning!
Definitely not what you would call cheap:
https://www.supercheapauto.com.au/brands/evapo-rust, but they say you can just pour it back in the bottle & keep using it, so probably worth it in the end.
No idea what it does, but there was no real residue left behind, as you get using vinegar.