You can also look for tanks with high polypropylene content. PP is less prone to cracking or melting with the acidic juices like cinnamon. It's also less transparent and looks foggy. Best bet is glass or metal. I never heard that minty flavors melt the polycarbonate. I would question that. It's acid that does it, like in citrus flavors, cinnamon and a few others, like pineapple. Somewhere, there's a thread that lists all the flavors that people have had problems with melting or cracking their tanks. Don't recall mint being on the list. I have a CE4 right now that has had spearmint in it for a week without problems.
