Both my Pur Hiker and my MSR Miniworks have pump parts with O-rings that need to be lubricated to work properly. The lubricant is a silicone that isn't water soluble, and isn't toxic anyway. If it bothers you, you may lube the O-ring with chapstick, but the lubricant won't last as long and may eventually eat the O-ring.

Bottom line, I don't worry about the lubricant on the O-ring. YMMV.
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--Ken B