Judy Hall's books on Crystals (the Crystal bibles) are some of the best physical books regarding what most crystals do, and how they work. Gurudas wrote some books back in the day too, regarding crystals and how they can heal through elixirs.
As well, the enemy does not gain much from tainting basic knowledge on how crystals work. As this makes it harder for their followers and useful idiots to use crystals to help the enemy. Though if you run across something that says 'sacrifice x to empower your grid' or 'chant x to clear this crystal' DON'T.
As for cleaning / charging crystals. The best and most effective method is setting your crystals in moonlight (4 hours) or sunlight (2 hours), this will clean and charge your crystals. Though I like to rinse my crystals beforehand with distilled water. Afterwards, store them wrapped in a cloth of some sort to help keep their energies.
Lastly, some crystals are toxic. Some are fragile. And some can be destroyed simply by putting them in water. Do your research before handling any crystals, and especially before attempting to make crystal elixirs with them.
I am in no way an expert in the field of crystals, but feel free to ask me any further questions. Thank you