1. Determine an opening date
A big anniversary or birthday is ideal. Set a calendar reminder or leave a note where you’ll find it as the date approaches. If the family time capsule openers will be another generation, leave explicit instructions with your estate so the capsule isn’t forgotten.
2. Select keepsakes to include
It may help to choose items around a theme, such as entertainment, your town or family milestones. Get everyone involved. Ask each contributor to write a note about his items on acid-free paper. Individually pack each item in a sealable polyethylene bag or small acid-free container. Avoid items requiring technology to view, such as photos on a DVD. (If you’re planning a long-term time capsule—say, five or more years—see the suggestions here.)
3. Select a container
The container should be large enough for all the contents and able to protect against pests, dust, light and handling. Plastic, metal and glass are good choices. Smithsonian Museum curator Don Williams suggests repurposing a large polyethylene terephthalate (PET) jar, the kind pretzels and cheese balls come in. Add a label on the outside that describes when the time capsule was created and when it should be opened.
4. Pack the container
Place the heaviest items on the bottom. Cushion fragile objects with polyester craft batting. Ask everyone present to sign their name on a sheet of acid-free paper and enclose it with the contents. If it’s a sealable container, drop in several silica gel packets to help keep the contents dry. You also can use “ageless” oxygen absorber packets; follow the manufacturer’s directions. If the container has a screw-on lid, seal it with a thin layer of melted paraffin or candle wax.
5. Store your family time capsule
Don’t bury it in your yard! This mini-archive should be stored inside your home, where the temperature and humidity are consistent. You can keep an opaque container on a bookshelf (if you won’t be too tempted to open it early). Store clear glass or plastic containers in a closet, away from light and heat.