Ok so what on earth can you do with formula cans? I asked the same question to my mother when she told me she was saving them. However, she put wrapping paper around the cylinder and cellaphane stuffed inside. Then added cookies into the cellaphane, and gave them to the neighbors for Christmas. So darling!
You could cover with cute paper, or paint them, and embellish with ribbon and chipboard. Use them for pens,cotton balls, army guys, whatever you fancy. I go through the small cans so fast, like one every day or day and a half. The larger can I go through weekly (I mix 2 formulas). If you would like some ever,until August, let me know. I currently have abot 25 small ones and some big ones. I am running out of space, and will start throwing them away if you don't want them. Might I suggest this would be a great gift for your sisters birthday, and will cost next to nothing!!