Personally, I never had success with coco-coals til I started using a Lotus Bowl. I think the main difference is having something on top to keep the heat in. If you use foil, you probably just need to make a good incubator for the coals. Also, are you lighting both sides of the coals? I might be wrong on this front, but I light my coals on a hot plate, heat til one side is red, repeat, then apply. Hope at least one of the things I mentioned helped you out.
Heya, new member here, so if I'm in the wrong place to ask a question, I apologize. Anyway, I was scraping some residue off my silicone funnel bowl, and a little piece chipped off the edge. It still works as far as I can tell, but I just wanted to know if I'm risking inhaling burning plastic, or if the material in question is safe despite the chip.