How to cleanse?

I'm very new to crystals and all things spiritual. Many of the terms used (for example, "cleanse," "charge," "intent") I don't quite understand. I recently bought some tumbled crystals (obsidian, labradorite, and fluorite, I believe) as well as some crystal bracelets (I'm not sure what crystals they contain—only that one is for protection, one is for knowledge and creativity, and the other is for the Leo star sign). How do I cleanse these? Do I need to charge them to work? If so, how again? And intent??