I believe that I read somewhere that you can melt down pewter for its high tin content to mix in with your lead. I do have a question however. I have also read that some pewter has up to 3% copper in it and some has as little as .25%. Will this ammount of copper affect casting boolits and prohibit good flow to fill out your molds? If so, how can you tell which pewter has the 3% copper and which pewters have only .25% ?