“Of the most common resins, polyethylene (PET) and polypropylene (PP) both have a translucent, waxy texture, and are the only non-foam plastics that float in water. The burning properties will discriminate between these two resins. PE burns rapidly, drips flames, smells like candle wax and, when extinguished, will produce a white smoke. PP, on the other hand, burns more slowly, smells like burning fuel, and does not drip flames while burning. PE is impervious to chemical solvents while PP will dissolve in hot toluene.”
And finally we could eat.