Hi girls...
Not feeling sure about posting this, but I think my conscience is forcing me. I SO don't mean to alarm or offend anyone, but I am very careful about heating plastic of any kind, especially in the microwave. There has been alot of press about this lately, at least in the U.S. Heating pastic releases dioxins into the food/liquid inside of it, and dioxins are known toxins and suspected carcinogens. There has been alot of news about not even leaving your water bottle in your car on a hot day, because that would cause the water to be unhealthy. Have you seen bottles/cups/products that say "BPA Free"? Those are safe to heat, as they don't have the same chemicals in the plastic.
Again...please don't think I mean to alarm anyone...but I feel I had to post this. Maybe try a google search on using plastics in a microwave, or any type of heat with plastics.