I have a lot of buttons, I really do. Unless they are new and on the cards. I have them strung together like others, Then sorted by color into gallon size bags and all of those put into one of those big fabric bin drawers in my cubby shelf. Then if I need a set of buttons i can just get out the right color bag and look through them.
I love the idea of mason jars. I already have a bunch of the old kind with the glass lids or with zinc lids that are full of all the old thread on wooden spools that I have. They look pretty great and are more for decoration then anything. The empty spools went in a gallon jar. I could do the same with buttons, but I am running out of room.