Up until a couple of months ago I was always confused with the little numbers and antonyms inside/outside of the recycling symbol. I had always thought you could recycle any type of plastic no matter what number it had! This idea was a misconception. There are some plastics that cannot be recycled because if they were to try it could harm the environment. Check with your local recycling center to see what kinds of plastics they recycle.
Here's a chart that may help sort confusion like mine, if you had any to begin with:
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(I'm hoping what they circled is the most commonly recycled plastics)