I'm currently reloading 6.5cm. I've put the brass in a electric tumbler with walnut media and it cleans the outside well. I've just noticed that there appears to be some red residue left on the outside of the cases which wipes off easily and I'm assuming the residue is also on the inside. I've watched some video's where people used a solution of hot water, salt, vinegar, and dish soap to clean brass. My question is, has anyone tried this and does it work? Or does anyone have any other solutions or liquid products to cleanse the inside of the case? Thank you