All types of abrasives must be kept clean and dry and, where possible, in the original factory packaging, unopened until ready for use. Moisture is the biggest enemy, which can cause clumping in abrasives such as garnet and bicarb soda. Steel grit and steel shot do not fare well when moisture is added; these abrasives will rust together into clumps making the material useless.
Careful storage also reduces injuries. Split bags of glass beads or steel shot can be a hazard underfoot. Spills should be cleaned up immediately.