Take care when cleansing your crystals. You mentioned salt, are you going to use dry salt or salt water? Please note that salt water (and water in general) can damage many minerals. Quartz crystals and its range of cousins are usually safe in water. You didn't mention what crystals you have, so I'll assume a wide variety.

Honestly selenite is the fastest, easiest and most effective way to cleanse your stones. I have charging stations throughout my house. White selenite absorbs all the negative energies and transmutes it into positive energy. You can do many stones at a time, let them rest for as long as you want.

Here's a link to more information:


http://www.tosots.com/CrystalHealing/crystal_care.htm

Sure, but only the hard stones like Quartz. Porous stones like moonstone, jade, malachite (never put malachite in water !), lapis lazuli would be better with an incense smudge.

I put a few stones together at a time, but only the really hard, shiny ones (like I said, quartz, aquamarine, etc.).