So, I placed my Lee 6 cavity mold on the shelf in my molding area in my barn - It used to be a spray paint room with a big blower providing lots of ventilation. This was last week. So, I finally get my alloy for 45 colt worked, and today I start to cast it in molds... Well, the !!#*&%$!! mud daubers crawled through the sprue shear holes and filled each cavity up with nasty mud/cement. I knew I can't use a wire brush to help clean it, so an hour of tooth brush and soapy water later, I think they're clean. Note to self: Always put molds back in the box.