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   ~ Produce is often coated to better preserve it during transit to the
   ~ grocery. Whatever are these waxes made from?

Kemp,
Many of the waxes are made from parafin (petro-product) and have in them
fungicides, pesticides. Whether they are gluten free I have no idea as one
would  have to look at all the ingredients of the
fungicides/pesticides/parafin wax.
Chana