If your having trouble keeping your pot clean, try some Plumber's flux, available at home depot or your local hardware store. Apply lots of it to the pot and it will burn off all the slag and excess garbage stuff in your pot. Beware though...you need to do it outside or in a well ventilated area because it will smoke and sometimes sparks a fire in the pot if its really dirty. I do this before every pour and have no problem melting all types of lead from wheel weights to the clean soft stuff.