I clean them and put them in a box, a light spray of Prestone Silicone lubricant, mix the cases around and then another light spray. The silicone is carried by a solvent, if you let the cases sit for a couple of hours and let the solvent evaporate there will be no contamination of the powder. The cases are lubed just enough that there is no drag when the cases are being sized. But I agree with Steve J, if the cases are clean you don't need lube for pistol casings when using carbide dies.