Most municipal recycling programs accept a lot of materials they do not currently recycle because retraining people is harder than sorting materials on their end, and not necessary since they sort it anyway.

After sorting they look for buyers of the raw materials. This varies depending on the market and quality of the material. Everything left over is sent to the landfill.

But does Seattle actually recycle all the plastic numbers? There are a number of places where all plastic numbers are accepted in the bin, but some (and sometimes all, depending on market conditions) of them are thrown into the trash later. The logic is that, overall, plastic recycling can be increased by not requiring people to decipher the codes.