Ever notice those recycling symbols, the triangles with the numbers inside, on plastic packaging and containers? I always assumed they meant the plastic was recyclable. But that’s not necessarily the case.

Those numbers are resin identification codes, and they tell what kind of plastic the item is made from. And not all plastic is created equal.

Identifying what types of plastics are recyclable can be challenging because plastics do not always carry a resin code and because not all recycling programs are equal, either . Generally speaking, though, some categories of plastic are more widely recyclable in the United States.