If memory serves, they did actually test some on a flight, with a man assembling the components in the bathroom and leaving a very small bomb under a seat. On the next flight, it went off and killed a single passenger, a Japanese man.
Not sure, but I think some of the liquid was kept in a bottle for contact lens solution.
It was Ramzi himself who did that.
One plan was to use nitroglycerin in an eye drop bottle, but I'm not sure that's what was used in this case, I think it was a binary of some sort.