The safer tubes mentioned above by Inaryn can be quickly and cheaply fixed to work as the others do. With just a Q-tip and a small amount of glue in the cap, the tags are removed with ease and without the added safety concerns of the other vials. I have done this to all of mine and have had no issue.
And as for the ease of identification. I color code the caps. Nail polish works. These caps have an outer ring and a center. I paint the outer ring red for cure, black for protective, and blue for fixes. Then paint the center different colors for healing amounts, the protective or the fix.
I.E. Red/Silver is Cure Crit Wounds. Black/Silver is Magic Armor. Blue/Red is Purify.