I thought I read somewhere (perhaps West System literature) that epoxy mixing cups should be wax-free, but System Three sells wax-coated mixing cups. I'd like to buy a large, cheap box of cups at the local warehouse store, but I wasn't sure if the wax would cause problems with the epoxy. I absolutely could not find any wax-free cups (except for the expensive ones at the boating shops). Anyone have any problems with generic wax-coated cups?