not all brake clean solvents work equally well,some leave a slight residue,dipping the mold in really hot soapy dish water with dawn soap and a good brushing with a soft tooth brush followed by some alcohol seems to clean fairly well then immediately heat the molds to remove moisture and coat the surface with mold release spray.
the guys are correct that the mold won,t cast well until its fairly hot , I generally want my bullets to look a bit frosted, and adding 5% tin to the mix of wheel weights helps both bullet strength and the mold fill out more uniformly.
http://www.midwayusa.com/Product/76...mold-release-agent-and-lube-6-oz-aerosol a build up of smoke soot from a wax candle on the surface until the molds surface is coated in fine black soot, will work but its not going to last nearly as long or work as well.
