making a HEAVY sandbag
I've become a real fan of sandbag lifting (especially shouldering, bearhug squatting and cleaning&pressing are great fun). Now the problem is I'm getting close to my bag's maximum capacity: I'm using an army duffle bag and it can only store about 75kg worth of pea gravel... Any ideas on how to make it heavier without going for a bigger bag? I've tried looking for lead shot, but here in Belgium they just don't seem to sell the stuff in smaller quantities (read: less than 1 ton's worth).
Any ideas would be greatly appreciated.