So I have been using a small glass cup of distilled water and was rinsing my dropper in it, of course making sure I emptied it as much as possible before, but Ive noticed that it doesn't take much to taint the water with a flavor that you may not want in your next mix. TFA Western for example is very strong and only a fraction of a drop will make your water taste like this and you can actually taste it in your next mix. I didnt figure this out for awhile until I repeated a mix that I knew was good and I could taste it. Who knows how many good mixes that I didnt like just because my water was not clean.