Your plant will need to be washed and rinsed well and replanted before you use it. Use organic soil and buy large river rocks to cover the soil so your cham will not be able to get to the soil. Make sure the rocks are very large so the cham cannot eat the rocks.
First thing you'll want to do is re-pot the plant using an organic soil. This should have no fertilizers or vermiculite (or the equivalent) for your cham to ingest. Add some sand to the soil if you want to improve drainage. Second, and I usually do this while the plant is out of the container, rinse the entire plant with cool water, looking out for any "visitors" and dead leaves/branches. Rinsing the leaves should get rid of any residue that may be present. Gently rub the leaves while under the water. After re-potting make sure to cover the surface with some good sized rocks that can't be ingested by your cham. That should do it!
Make sure to read your labels carefully! Many so called "organic" potting soils still have added fertilizers, etc. My local hydroponics shop carries many organic compost/potting soil mixes that clearly state their contents on the label.