I agree with Mcne, except that steel shot is magnetic, not always a great idea on top of speakers with magnets. If you cannot find lead shot at a shooting supply, try finding it at a dive shop.
Dive lead for scuba, is coated in copper to conform to current laws about water safety. Completely non toxic and still non magnetic.
Dive lead for scuba, is coated in copper to conform to current laws about water safety. Completely non toxic and still non magnetic.