If you place them in a magnetic field and bang them with a hammer it should jolt the molecules into alignment with the magnetic field. I'm not sure how well however.

If I'm not mistaken, you're working with lead. If lead gets hot you can breathe the vapors and it could be thrown into the air as dust. I worked with lead for many years and my advice is to steer clear of it. You could also expose yourself to other heavy metals.