I don't use the wand, I favor plastic toothpicks and never double dip. With some of the sandalwood oils that I bought years back, I did use the wand and started to notice an accumulation of particulates in the bottom. Probably not 100% dead skin cells, but surely not 0% either. Does it affect the composition or smell? Really I have no idea, but erring on the side of caution for me is as simple as taking a toothpick out of a box and dipping/swiping with that instead.