I can't have anything that is even remotely ball related just laying around because my dogs are obsessive about them. I do use them for training and it's the greatest thing ever!
This is how it is with Jerry. No balls are allowed in the house because he will never stop playing with them and it goes something like this:
gnaw the ball
put the ball down and stare at it intently
when it doesn't move on its own, paw it
chases the ball everywhere
get it stuck under the couch
dig around under the couch
I lift up the couch and retrieve the ball
repeat all of the above, with him also dropping the ball in my lap so I'll throw it
So, no balls in the house, ever. He still tries to sneak them in sometimes. They are useful in training - he will do anything you ask if you are holding a ball.
Here he is, trying desperately to get one back.