how do you use crystals for OBEs?

Certain crystals and stones have frequencies that interact with our chakras and aura. A link to some good descriptions is here: Crystals, Healing Crystals, Healing Properties of Crystals, Gemstones, Crystals and Minerals, Charms and Crystals at Peacefulmind.com

Someone using crystals for this would find ones that resonate with the 3rd eye chakra and crown chakra. My guess is clear quartz and amethyst would help. These can probably be used to help dreaming too, and there are other gemstones that can help with dreaming and lucid dreaming too. Clear quartz is a all-purpose amplifier and amethyst is used to help with ESP like OBEs, AP, and any kind of meditation or energy work. Getting some protection stones like pyrite to put in your room could help too.

Then, once someone gets some quartz and amethyst, they would just set them beside them as they sleep. On a night stand next to their head, or even in their pillow. I would not have them directly in the pillow every night though, as its my opinion that it would be a lot for your energy body to handle. Sleep without the influence of crystals on your energy body gives it a chance to totally refresh itself. But using them every weekend or whenever attempting OBEs would be fine. Then just proceed normally with the OBE, as crystals and stones are always working.