Cleaning old pots?

[stringstretcher]

I have serveral old cast iron dutch ovens that were left out in the elements and have a pretty good amount of rust, inside and out. What is the best way to get these usable to smelt in and what do you do to your pots after a smelting session to keep them in like new shape and no rust?

[MT Gianni]

To cook in you scrub them, coat them in oil, burn it off and do it again. I have heard that a bottle of coke will soak the rust off but have no experience. Please keep cast iron inside. Cooking cast iron is generally coated with an oiled paper towel after use especially if the patina is scarred. I leave a napkin between the lid and oven to let moisture vent.
If it is for casting only, outside rust won't hurt it. You need oil underneath the rust to float it off. Boil some water in it, then pour out the water, and add cooking oil. When it has cooled enough to work it, scrub the cast with a rough cloth, burlap is best but use what you have. Keep at it until most or all of the rust is gone. Any oil will act as a flux when you smelt into ingots. I would flux heavily as you melt ww as you will be bringing up rust for a while. Gianni

[10-x]

Cup brush on a 4 1/2" angle grinder, outside with eye protection. Check for CRACKS, build a small fire with hardwood, set pots on fire, add wood and "cook" them for an hour or so. Allow to cool, check for CRACKS AGAIN,clean with wire brush, "O" steel wool or similar. Keep them inside after use.....and most of all "use often" to smelt or cast.:castmine:

[imashooter2]

Brush loose stuff out with a rag. Place on heat source. Fill with scrap. TA DAAAAA! Ready for smelting.

After smelting, place on shelf in shed so it doesn't get rained on.

[Pitmaster]

You can put it in a self-cleaning oven but the house might smell for a little. If using a propane burner set it on the burner and crank it up till the rust burns off.

[zampilot]

"I have heard that a bottle of coke will soak the rust off "
It works, that's what a good Tanker uses to free up rusty end connector bolts! Nowadays they have all fancy penetrating oils and such.

[Le Loup Solitaire]

Hi, Another effective method for getting rust off of cast iron is to immerse the cast iron in white vinegar. But not for too long as vinegar contains Acetic Acid and that not only eats away the rust, but it attacks the iron too. A few hours should suffice. It bubbles constantly and the by-product floats to the surface and stinks like a PO'd skunk, but it is effective. Drain and rinse the item when you're satisfied with the appearance. Coat with any kind of oil to prevent rust from starting again. The vinegar "dip " can be shorter if you first use a wire brush to get the heavier scaling off. "Coke" (coca-cola) has carbonic acid in it and that works altho slower. Don't use Sulfuric or Hydrochloric acids as they "fume" and they can really mess you up bad, (healthwise), if inhaled...even a little! Whatever cast iron you use, mark it in some way so that it doesn't get food cooked in it. Enjoy casting. LLS