1st day of school time capsule

Tonight I have been looking for something fun for the kids to do the 1st day of school. I came across the cutest idea. Create a time capsule! It suggested using pringles cans, but I am going to use baby formula cans b/c I have a lot of these that need a good use. It suggested you have the children have a sample of their handwriting, tracing of their hand, self portrait...any thing else you can think of, make a fun ceremony of it, and put it away for the year. Then, at the end of the year, have the kids to the same thing, and then bring out the capsule and compare. I always enjoy looking in my children's math workbooks to compare the difference in their handwriting throughout the year, so I think this will be a fun activity for them! I was thinking even to take a photo of them to include in the capsule, or to decorate the outside of it.