How and why to clean crystals?

Crystal is easy to break so we must be careful to do that. Regular purifying to clean the crystal can remove dust and body oil. Purify the negative energies and frequency.

Now we do not prefer to soak in salt water, it maybe destroys the crystal surface. Salt is a corrosion material.

Quality is soft crystals must not use salt water. E.g. Pyrite, Selenite, Angelite, Malachite, etc.