Inorganic Mounts for Orchids

[dnatural1]

In a recent thread on Ghost orchids a couple of contributors said that it is possible to use inorganic mounts for orchids. I like the idea of long lasting mounts and once tried to grow Sarcochilus falcatus (an epiphytic orchid native to Australia) on the outside of terracotta "jug". I filled the "jug with moist sphagnum moss for moisture retention. Did not persist far with the trial as I became concerned that the clay may exude salts that are toxic to the plant.

Questions that come to mind include: what minerals can leach out of terracotta one has to be wary of?, can these be removed by pre-soaking the pot?, what other mineral mounts have been tried? How do inorganic mounts compare with cork?