As I grew up and began collecting my own buttons, I too kept them in a large jar. When doing projects I would pour them out on the rug and dig around till I found what I needed. As much as I still enjoy digging through piles of buttons, it can make me a little crazy.
I recently found the perfect use for some of the many different sized jars that I cant seem to throw away. I use them to organize the buttons by color/style/ size. Now my buttons are much easier to access, and pretty too.