I have found lee molds to be a wonderful piece of equipment to learn mold maintenance and repair with , as well as what to do & what not to do to a mold .
So I would remove the sprue plate and resurface the top of the blocks and the bottom of the sprue plate , after reassembly pay special attention to applying lube around the sprue plate screw , top of the blocks , and bottom of the plate .
Galling seams to do quite a bit of damage to aluminum molds .