Well, you know how feel about plastic and my kids. I’m not a fan. So, I’ve been hunting for the perfect cups for them. I also don’t like cleaning up spills so I’ve had to factor that into my search. I came upon the Ball jars. I love the idea of them using these as their cups. So, I bought a dozen and drilled holes for their straws into the lids of them…which after a while began to rust. Plus, it’s not easy to file down the holes after they’ve been drilled, making the inside of the lid sharp. Not so good.