Evan that stuff is called Aliflor, I think.
http://www.quarteracreorchids....
On the charcoal question, it might depend upon what kind of wood you're burning. From what I've read, pine resin may be harmful to orchids. Same may be true of other woods with aromatic resins, I guess. On the other hand, talk to anyone who grows orchids and they'll tell you dozens of things that orchids might or might not be sensitive to.
Time for a funny story, a very knowledgeable orchid grower on Dave's other forum declared again and again how sensitive orchids were to any kind of soap. While I was away this summer, my neighbor kindly sprayed my Brugmansias with soapy water solution to keep the spider mites in check. I'd neglected to tell him that I usually move the brugs away from their position shading the shelves of orchids. When I got home, the brugs looked fantastic, and of course the orchids had been thoroughly soaped as well. No harm done that I could detect.
Where orchids grow naturally, they sure as heck are exposed to a lot of wacky stuff, and they survive!
