Get a nice thick and even coating of your fat of choice all over your pan. Since my pan only had damage on the inside, I didn't coat the bottom of my pan, but if it's necessary for your job, do one surface (inner/ outer) at a time. Pay attention to the smoking point of lard or the shortening you're using! Lard can stomach from 370ºF to 400ºF, while many vegetable based shortenings will only tolerate a lower range, say 350ºF to 370ºF. Use a higher smoking point fat if you can.