Although some companies advertise their plastic containers as "microwave safe", radiation is pretty strong stuff, so I've never thought it was a good idea to blast microwave radiation waves at a piece of plastic that is holding food you're planning to eat. This could send all sorts of chemicals and toxins leaching into your food.
That all said, if you insist on using the microwave, remember to transfer your food into ACTUAL microwave safe containers, such as as ceramic or sturdy glassware first, then remove any plastic coverings. Worried about food exploding all over the insides of your microwave? No worries, cover your food with a plate instead of cling wrap!
Thanks for reading through my rant!
P.S. In case you didn't already know this, metal dining ware should also never go into the microwave, this includes aluminum/tin foil. This is dangerous and could cause a fire!