Mostly, I have used the stainless steel spoon, and wood sticks to knock off the dross that clings to the inside of the lead pot.
But, I acquired a pot in a junksale that was badly rusted and had dross caked on the sides. I used all the above, including a cold steel chisel, and then use a wire brush on an electric hand drill to remove much of the remaining dross, and the rust around it. Because of pitting, I used a grinding wheel on my handdrill to smooth out the sides and eliminate most of the pits.
I then heated the pot up veery hot,and oiled it to "cure " it just as you would a frying pan. This burned the oil into the metal.After that it has been used to make lead several times, and is working just fine. The shortening or oil forms a scale( which fills the pores), that resists further oxidation. Even under the higher heat of molten lead, dross does not stick to the sides, and is easily cleaned. I have not thought to try this process with modern Electric Lead pots, but its a thought. :hmm:
I did inspect the pot for how thick the iron was before beginning the project. You are limited to how much metal can be removed to " save " an old pot that has been neglected like the one I found. The one I found was very thick cast iron.