Sand and shot?

I've tried lead and sand and have settled on concrete powder. It's extremely dense and dead for sound. Non toxic and plentiful/cheap.

I used a mixture of sand and shot by filing first with sand and then pouring in the lead.
You can get blu tac or 3m substitute at any hardware or general merchandise store.

Once again I thank you for your knowledge and advice. I called a gun shop to inquire about the shot and was told Walmart has this. Maybe I can get the blu tac at the same time. I'm on my wayyyy :)

Blu-tack = Audio duct tape

I used generic bluetack on my B&W805s stands.
I made it super thin by kneading it with my fingers until them bled!
1/32 inch thick (any thinner and it 'tears')
The sound without, and screwed to base was too 'tight' in the bass and a bit bass shy.
With the bluetack substitute the bass came out just enough to be perfect!
The generic worked for me... just remember to knead it a LOT before using it. The more the better.. (keep pulling it in to a long strip then fold, repeat. after a dozen strech and folds, twist it up about 30 twists, real tight. then repeat streching and folding. then roll it up into a ball or tube and use it anyway you want.
Makes the stuff much much better.