I've got half of a delicious pepperoni pie from La Rosa Pizzeria on South Broad in my fridge that I plan on finishing tonight, but once I'm done, I won't be recycling the box like I normally do.
Call me stupid, but I didn't know you weren't supposed to put your greasy pizza boxes out with your cans, bottles and other recyclables, as Philly311 reminded residents in a tweet Monday afternoon.
Why? CityLab explained two years ago after receiving a reader’s question. The problem is the cheese and oil stains left behind, which cause paper contamination.
Per Citylab:
Even if you remove the crusty cheese and sauce the slices leave behind, grease will have already soaked into the cardboard, ruining it for recycling. In a single-stream system (where bottles, glass, paper, and more all co-mingle) residue from other items in the bin could also contaminate the cardboard. Food and oil can't be separated from paper in the pulping process, so once paper is soiled, it's a done deal.
Citylab noted the greasy boxes can be processed through high-volume composting with other organic waste, but if that's not an option, just throw it in the trash.
And remember, you can always check what you can (and can't) recycle in Philadelphia on the Streets Department's website, where you can also find out how to get a bin, how to separate trash from recyclables and other information on what to do with your waste.