Originally Posted by
corporate-wage-slave
My mother had some home made marmalade confiscated about 6 years ago, she still talks about it in vivid terms. But the hapless agent who unfortunately had to deal with mum tried to argue using the following test: imagine a slope of shiny metal at 45 degree, place item on top of the slope, leave it at ambient overnight. If the item has moved 1 mm overnight it is a liquid.
Somewhat time consuming to test. Liquids have a fixed volume but are free flowing; Tiger Balm would fall somewhere between gel and paste. Maybe the acid test, is can it be used as a constituent in an explosive device? But there are plenty of solids which fall in to that category too.