I've been keeping jars like this for years now (even before I met Mack) it's good to keep just to go through and look at the years, they go by so fast!! Recently I've used mason jars but I used to use old hat boxes. Any container will work, just keep putting things in. It's so great to look back and reminisce.
Some items in our memory jar :
*we used to write fun things we did together on a scrap of paper*