Now that I am a year old I am knowledgeable about certain things.
I am not as wise or experienced as Della or Fenway, but I have learned all about chewing tennis balls.
Here are some guidelines:
The color doesn't matter, take whatever you can find.
Start by pulling off as much of the fuzz as you can. This may take some time.
Then hold it tight against the floor and gnaw it with your back teeth.
Eventually it will split and you can see if anything is inside. There usually isn't though.
It works every time, I am on my third one already!