I have many molds, both iron and Lee aluminum.
One of the nice things about the Lee molds is that you can bring them up to heat fast either by sitting them on the edge of the pot or by dipping the bottom of the blocks in the metal for a few seconds until the lead falls off when you pull the mold out (do NOT do this with iron molds!)
All molds do need a good going over with a degreaser and q-tip. and then I always smoked the cavity with a flame to assist with release. About a year ago I tried using a spray product from my auto store that sprays a graphite compound in a solvent. The solvent evaporates and leaves a micron thick coating of graphite in the cavity. I also spray the top surface of the mold, the sprue plate hinge and the locator pins..
This worked so well that I did all my iron molds the same way. It solved the sticking problem of a Lyman mold that had been an issue for years. It is a messy spray so do it outdoors away from doors, walls cars etc. The coating does not seem to wear off and on my iron molds helps with rust prevention.