Test method to quickly distinguish PU leather and PVC leather

PU leather and PVC leather are both artificial leather and simulated leather, but they are not the same.
The fastest test method to distinguish PU leather and PVC leather is to soak in gasoline.
How to do it?
Cut a small piece of fabric and put it in gasoline for half an hour before taking it out. PU leather will not become hard or brittle, but PVC leather will become hard and brittle, so you can distinguish the material.