The hoaxes I receive are craftier than ever, blending truth, half truths, urban legends and lies with fuzzy rules that make it impossible to use them.
I always always check by searching one of their statements with Google and reading what the hoax-busters think.
Inert containers are best, for example heat-resistant glass, ceramics and good old stainless steel. ...
...It is now generally accepted that a principal source of dioxins are various combustion processes, including natural events such as wild fires and even volcanic eruptions.
Researcher dispels Myth of Dioxins and Plastic Water Bottles
Here is one more: snopes.com: Microwaving Plastic Releases Cancer-Causing Agents