Do not discard bad diffracting crystals! They can be very useful, too. Try to improve diffraction by crystal annealing, varying the solvent content or use your initial crystals for seeding.
An assembly kit designed for crystal annealing at your home source
Crystal dehydration - the most effective method to improve the diffraction properties once you have crystals. Try our Dehydration Salts & Crystal Dehydration and Salvage Kit!
The kit is designed for the preparation of a seed stock solution by using a glass bead and a microcentrifuge tube as mortar and pestle for crushing of seed crystals