▁ox id ation ▁of ▁the ▁iron ; ▁the ▁f ats ▁and / or ▁o ils ▁protect ▁the ▁metal ▁from ▁contact ▁with ▁the ▁air ▁during ▁the ▁reaction , ▁which ▁would ▁cause ▁rust ▁to ▁form . ▁Some ▁cast ▁iron ▁users ▁advoc ate ▁he ating ▁the ▁pan ▁slightly ▁before ▁applying ▁the ▁fat ▁or ▁oil ▁to ▁ensure ▁that ▁the ▁pan ▁is ▁completely ▁dry . ▁ ▁The ▁surface ▁is ▁hydro ph ob ic ▁and ▁thus ▁highly ▁attract ive ▁to ▁o ils ▁and ▁f ats ▁used ▁for ▁cook ing ▁and ▁thus ▁when ▁used ▁with ▁a ▁layer ▁of ▁oil ▁prevents ▁food s , ▁which ▁typically ▁contain ▁water , ▁from ▁touch ing ▁and ▁cook ing ▁on ▁to ▁the ▁hydro ph il ic ▁met all ic ▁cook ing ▁surface ▁that ▁lies ▁beneath . ▁ ▁The ▁season ed ▁surface ▁will ▁d eter ior ate ▁at ▁the ▁temperature ▁where ▁the ▁co ating ▁breaks ▁down . ▁This ▁is ▁typically ▁higher ▁than ▁the ▁smoke ▁point ▁of ▁the ▁original ▁o ils ▁and ▁f ats ▁used ▁to ▁season ▁the ▁pan . ▁Thus ▁old ▁season ing ▁can ▁be ▁removed ▁at ▁a ▁sufficiently ▁high ▁temperature , ▁as ▁found ▁in ▁o ven ▁self - clean ing ▁cycles . ▁ ▁Care ▁ ▁As ▁with ▁other ▁cast ▁iron ▁vessels , ▁a ▁season ed ▁pan ▁or ▁dut ch ▁o ven ▁should ▁not ▁regularly ▁be ▁used ▁to ▁cook ▁food s ▁containing ▁tom atoes , ▁vin eg ar ▁or ▁other ▁acid ic ▁ing red ients , ▁as ▁these ▁food s ▁will ▁eventually ▁remove ▁the ▁protect ive ▁layer ▁created ▁during ▁the ▁season ing ▁process . ▁Cast ▁iron