How do you get rust completely off of a dog tie out ?

Coke is your answer, just soak the tie out in coca cola and use aluminum foil to do the removal:

https://www.youtube.com/watch?v=sTo2GW_StTg

Soak it in vinegar.

Here's a post that might help https://www.reddit.com/r/dogs/comments/4t4wfu/discussion_rust_proof_tie_out/

Hello. A soaking in vinegar is indeed the easy way to remove rust.

WD-40 works well for quick removal of rust.

Soak in vinegar, soak in Coca Cola, WD40 and rub with some aluminum foil or steel wool

Navel Jelly or Rustoleum Rust remover works great

Hi! By a cheap bottle of coke or cola (I have used both) and soak it in the liquid. Use a dishpan or larger container depending on the size of the rusty item. My husband thought I was kidding until he saw how the rust came off some old tools. Once cleaned of rust, spray with a rust retarding product like Rustoleum. Good luck!

A stiff wire brush and WD40 or naval jelly.

I'd suggest this: https://amzn.to/3x6tXSO

Simply soak the rusty metal object in white vinegar for a couple of hours and then just wipe to remove the rust. If the object is too large, simply pour white vinegar evenly over the surface of the object and give it some time to settle.

You can simply soak in vinegar for hours, then just scrub it down. There's a possibility that it will rust as it driees, so I suggest to coat it or paint it.

Hi Emma, hope this helps you out,

Simply soak the rusty metal object in white vinegar for a couple of hours and then just wipe to remove the rust. If the object is too large, simply pour white vinegar evenly over the surface of the object and give it some time to settle, remember to rinse and dry once the rust is gone.

Using Aluminum Foil to Remove Rust

https://www.merrymaids.com/cleaning-tips/tidy-home/aluminum-foil-for-cleaning/