This works for small amounts of oils or vinegars.

Go to any camera shop where they develop film. Ask for their extra plastic film canisters, the white ones, not the blackones with the gray top. The white ones you can almost see through but not quite, those lids pop off, but only with alot of effort.

Try one or two of those.

I also collect these little useful FREE canisters from camera shops for carrying pills, coins, fiber powder and all kinds of small amounts of creams, meds and rings while traveling. It's my best life improving tip.

small freezer ziplock bags work too/double bag it - but they are expensive and take up more space in your purse.