during my bachelor thesis I used glycerin to clear parasites. For this you put the parasite in one drop of EtOH, overlay it with glycerin and incubate it (36°C) for 24h. After that you transfer the parasite in waterfree glycerin and fix it (on a slide) with some paraffin. Durin this precedure the water inside the parasite is changed with gylcerin and it appears somewhat clearer.