Well, what does the number 7 mean anyway? Sometimes it tells us right on the product: OTHER.
Well, what is OTHER? Literally, anything other than numbers 1-6.

Here is a list of the recycling codes
You can find extended descriptions of each resin category from the Plastics Web

1: PET, Polyethylene Terephthalate (PET, PETE, APET, RPET)
2: HDPE, High Density Polyethylene (HDPE, PEHD)
3: PVC, Polyvinyl Chloride (PVC, Vinyl)
4: LDPE, Low Density Polyethylene (LDPE, PELD)
5: PP, Polypropylene
6: PS, Polystyrene
7: Other, including but not limited to
Polycarbonate (PC)- common plastic associated with BPA exposure
Copolyester- the increasing popular substitute for polycarbonate water bottles, usually advertised as ‘BPA free’
Polylactic acid (PLA)- a biodegradable plastic derived from renewable resources such as cornstarch or sugars.
Acrylonitrile butadiene styrene (ABS)- petroleum based plastic used to make light but rigid products
Nylon (PA)- generic name for a family of polyamides makes anything from pantyhose to skateboard wheels
Acrylic (PMMA)- petroleum based plastic, light and cheap, but brittle under impact

The list can go on, but the point is all number 7’s are not created equal. How can one tell? Sometimes if you read the package it will tell you. Many manufactures that use PLA (the biodegradable plastic) want to advertise the fact that they used a renewable resource for their product. If you are not sure, you can contact the manufacturer as ask them. You deserve to be an informed consumer!