The sand scrubbing is done to level the stones after they've become dished out from use.
If it's the higher grit stones that you feel have glazed over, just soak them in water for several minutes and use them. Any glazing will be removed by the work. Remember to keep the 220 and higher grit stones wet while you work. At the last stages of sharpening, you can let them dry a bit to let the mud build up and form a polishing slurry. Rinse before storing.
The lower grit stones, especially the 80 grit, tend to just grind down before any glaze has a chance to build up.