For a long time, plastic clamshell takeout boxes and disposable drink cups from fast food restaurants were almost impossible to recycle. They are commonly made from hard-to-recycle No. 6-grade plastic, also known as polystyrene. But things are changing: Major supermarkets and fast food retailers are switching to No. 1-graded plastics, or PETE (polyethylene terephthalate), which is the most commonly recycled plastic. Since these containers have the look and feel of No. 6 plastics, check to see if the recycling mark is a No. 1 -- if it is, you can recycle it.