How to Strip Cast Iron with Lye (Sodium Hydroxide)

This can also be done with Easy-Off Max Strength Oven Cleaner (The one with the yellow lid) and trash bags but it is much more expensive, especially long term.

• The lye product being used absolutely needs to be 100% sodium hydroxide crystals. Rooto and Roebic are sold at Amazon, Tractor Supply, Ace Hardware and Lowe’s and are 100% lye
• One pound of lye crystals per five gallons of water is the formula/ratio. Always add the lye to the water, never the reverse— it will create an exothermic reaction, which can boil up and splash on you. Even when mixing and using lye properly, always use skin and eye protection, and protect clothing or wear clothes that it won’t matter if some might drip on them
• Any sturdy plastic container capable of holding its volume in water, with a secure cover to keep out inquisitive children or pets will work. I use hinged, lidded totes that I purchased at Lowe’s. If they are used outside they will typically only last a couple of years before they get brittle and crack
• Depending on how thick the build-up on the piece is, it will take from a few to several days for the lye to soften and dissolve the crud. Be sure to rinse the piece well before proceeding with initial seasoning
• Other things about the lye:
  • The warmer the lye solution is, the faster it works, so in a sunny spot is best
  • Keep another container filled with fresh water or a hose nearby to rinse the item being processed so you can handle it without fear of skin irritation
  • I keep vinegar handy in case there is ever any issue, it neutralizes the lye immediately
  • Even after rinsing, residual lye solution will make the piece slippery, so handle carefully
  • You can leave a cast iron pan in the lye bath virtually indefinitely without concern
  • Even when the solution over time becomes black as coffee from removed crud, it will still be quite effective
  • Rubber gloves are your friend
• Since lye will not remove rust, the usual protocol when using lye is to de-crud with lye first, then finish with 50/50 vinegar and water soaking in 20-30 minute intervals and scrubbing with 0000 Steel Wool
  to take all the rust right off. Don’t leave the iron in the vinegar and water too long at a time because it will pit the iron
• It may flash rust as soon as it dries, have your oven pre-heated to around 250 degrees, pull it out of the water, towel dry it and put it straight into the oven to finish drying
• I have had great luck for some time now actually wiping the piece down with shortening or lard before it is dry. I never have any flash rust when I do that
• If there is a little flash rust, put a little shortening on it and wipe it all back off immediately and start the seasoning process

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