What kind do you use?
I used to use the playtex ones, you know with the toy story designs and such but decided no more. I was tired of their messes and cleaning them if they became lost. Plus 7 dollars for two?! Nope.
So we decided to try the take and toss ones. 5 for like 3 dollars. I love them! They are great for Bishop and my other sons as regular cups. I'm going to buy like 3 more sets of them when we move so I can have a bunch of kid sized cups.