Put em to work. Like!

I used the gravel method in the past. Duct tape it to my cement mixer, then turn it on.

I've thrown in a box if 1/4" square nuts and did the shake, shake procedure.
I'm not a big fan of internal coatings, see a few go bad and make a real mess.
Acetone was the only thing that dissolved the coating inside.
Maybe it was an isolated case. :bigthink:

I have heard Coca Cola works good if you let it set overnight.

The "Works" toilet bowl cleaner works real well on rust. About 20-30 minute soak. Rinse well and neutralize.

:bigthink:

A piece of chain can be used to dislodge stuff. Keep one end on the outside and just pull it out when finished.

I've used nuts and muriatic acid to remove the rust. Then Kreem to seal it after.
https://www.google.com/#q=kreem+kit

I was amazed at the amount of rust, ect., that the nuts method removed. I added a bit of gas to the procedure, shook and rinsed many times. While your there, now would be a good time to reseal the tank nipple, and repaint the tank if desired.

Maybe use gravel but metal nuts shaking in a container with some gasoline in there too?
No thanks.

Dad use to use the gravel method, dry pea gravel.
Then he stuffed/wedged the tank into the rear wheel of another tractor.
With foam cushions and bungee cords to the tire chains.

Then sent me out to mow the lawn(s).

A 12hp tumbler.

X2 on the Kreem.

X2 on the Works