If you can't finish that bowl of pasta salad you made and plan on saving it for later, don't cover the bowl with plastic cling wrap. Plastic wrap is made from polyvinyl chloride, which when incinerated (most cling wrap goes from our homes to the trash to the incinerator) emits toxins into the air. There's also a risk of toxins leaching into food when cling wrap is microwaved at high temperatures. The simplest solution? Place a slightly larger dish on top of the bowl in the fridge. It'll still keep your food fresh.