I've not seen this before - a combination of recycling symbols on the same package.
The package is a 7 (Other), but it is 5 (polypropylene) compatible. How is this determination made? The SPI website doesn't have anything on classification, so what does it mean to be comparible?
Certainly I understand polymer comptability from both a practical and thermodynamic viewpoint, but I'm not sure that just any old processor would be willing to take a "polypropylene compatible" bottle from just anybody. That seems like a unworthy risk. The bottle manufacturer can suddenly say that their bottle is compatible with another resin stream? If anybody knows, please inform me as I am quite curious.
P.S. Today's "Ph.D. Commics" is terrific.