Duncan Wither

Cast Iron Pans

Maintenance

After initial purchase, wash with hot soapy water. Rinse well and dry completely.

Washing:

• Wash after use with hot water (no soap) and a scrubber or brush (non metal). Use salt if you need an abrasive.
• Dry Thoroughly with a towel
• Rub (with paper towel) with vegetable oil after drying
• Buff with clean paper towel to remove excess.

Source.

Seasoning

• Wash With Soap
• Dry Entirely
• Buff with vegetable oil
• Place upside down in preheated oven (225 degC) for 30 minutes
• Re-buff with oil
• repeat 3x
• Leave to cool in oven

Source Other sources suggest once for an hour at 190 degC.

Use with low-acidity food for a while to build up the layer of seasoning.

I read (but have no source) that highly oxidisable oils (like those you have to store in the fridge) are better because they oxidise so readily (there was a bit more science to it if I can recall) but again, I can’t find the article.

This one from man cave chef seems to have some good arguments for grape seed oil.