Yes, you can use eco-friendly ziploc bags in the microwave! However, be careful not to heat food too much. You should never reuse a plastic bag more than once when heating it in the microwave. This is because repeated heating will cause the plastic to break down and release harmful chemicals into your food. It's also very important that you don't heat anything that is already hot (or could become hot enough) to cause an explosion inside your microwave. The same goes for any foods that might already be very hot before putting them in the bag (for example, if they were cooked on a stove).