K.P.
Put the bottles away- I mean completely out of sight. Then you put out the sippy cup with milk and leave it out. She will scream and cry, but eventually she will take the sippy. It sounds like she still uses it at home b/c she can, especially if she isn't giving them a hard time at daycare about it. My son was like this with his binky. He only had it at nap time at daycare, but begged all night at home. Finally, I put them all in a ziploc (including the daycare ones) and put them in the attic. A few really tough days, but he never looked for them again!