Real essential oils won't dissolve plastic. Fake ones? Watch the horror show.
Use a disposable styrofoam/polystyrene cup. The white kind works best.
Drop the oil directly on the inside of the cup. Wait 60 seconds.
Look for holes, melting, or dissolution. Any damage = synthetic chemicals present.
Your oil didn't damage the cup. This is a good sign of purity!
Pure essential oils are distilled from plants and don't contain petrochemicals. Fake or adulterated oils often contain synthetic compounds like polysorbates, mineral oils, or solvents that dissolve polystyrene plastic. This is the same reason some essential oils are sold in glass bottles only.