The invention relates to an optically active ionic liquid containing a cationic species having a heterocyclic ring; and an anionic species. The methods can include feeding a phagostimulatory agent to a leech; inducing a regurgitation in the leech, the inducing including placing the leech in an environment having a temperature of less than about 0\xb0 C. The invention enables automatic loading and unloading of pads on the lens making machine.