Q: How can you tell the difference between polypropylene and PVC (vinyl) CD sleeves?
A: The fastest way to determine of a CD sleeve is polystyrene or vinyl is to give it a good sniff. Vinyl has a distinctive scent. Around the office, we've described this scent as being similar to a new shower curtain, a fashion doll and one of those big bouncy balls you can buy at the supermarket. Can you imagine that smell, now? That's the smell of vinyl and polypropylene doesn't have that smell. (Although polypropylene that has a lot of recycled content in it also has a distinctive odor, but that's a different smell all together.)