Underground Time Capsule

Why didn't they have cool toys like this when I was a kid?:

All kids like burying things, especially if they have the option of digging said things up later. That's why this Underground Time Capsule is so great. Not only is it designed to go underground and hide precious objects for later retrieval, but it makes the whole process easier by having a screw-on rock at the top, allowing you to add new items without digging it up.

When I was about fifteen I read a National Geographic article about a time capsule that a New England man found in his home that had been passed down for several generations within his family. MRI scans revealed several artifacts that appeared to have been gathered from George Washington's first presidential inauguration in 1789 but upon finally opening the wooden box it was revealed that the items were collected from the celebration of the 100th anniversary of his inauguration in 1889, still quite interesting and historically valuable nonetheless.

After reading that article I was determined that I too was going to build my own time capsule, not to mark any one historical event but rather just as something to send to my future self; some pre-planned nostalgia if you will. So I gathered together many different articles that would fit into the shoe box I was using as my capsule (yes, I went high-tech): a newspaper, a few magazines, toys, coins and bills, and many other things I've long since forgotten about but basically anything I thought might be cool to look at after a long day of driving my flying car around. I then wrapped the box in several layers of heavy paper, plastic wrap, aluminum foil (was I planning ahead for water or microwave radiation? I have no idea) and then encased the entire thing in many layers of heavy duty duct tape with a large label reading "Open in 2020".

And now it's sitting on the top shelf of one of my closets upstairs as I type this, waiting for the day that I planned as its grand opening. I sealed it in the summer of 1989 and chose the year 2020 as that opening day, partly because it seemed a long way off and partly because it's a round number that sounded really futuristic at the time. But now I'm faced with a quandary: it's been almost twenty years since I sealed the box up and I only have another decade before the opening date but the sealing up process is still relatively sharp in my memory, so I'm considering moving the date back a decade or so or even encasing it in a more durable container and passing it on to family to be opened after an entire century and my own death have long since passed. Of course, if I lived to be 115 and was able to open it then that would be the shit but with my diet and drinking habits I'm not betting on clearing a century. So, what do you think I should do? Any thoughts or ideas will be greatly appreciated.