Lately I’ve been using the RED version of the Evaporation trick. Since I travel frequently I don’t always have the same access to juice that I’d have at home. For example when I travel my “orange juice” is actually Tang. For the red juice when I travel am am staying at a hotel that has breakfast I use the following concoction:
Fill the bottle to the desired level with cranberry juice. This will work, however I prefer my juice a little darker, so I add a drop or two of coffee creamer and that will make the juice opaque.
Hope that helps!