1 GUIDELINES FOR SELECT ING AND PRESERVING ITEMS IN A TIME CAPSULE Paul S. Storch Project Specialist II/Collections Liaison Historic Sites and Museums Division Minnesota Historical Society Saint Paul, MN Introduction The long-term survival of the ti me capsule and its contents depends on many factors including the construction of the capsule, the material s chosen for inclusion and the location of the capsule. The following guidelines focus on the items most commonly chosen for capsules. They are intended to help you select and prot ect items to last for years. Some Things Last Better Than Others When selecting items made of paper, choose a good quality paper. Avoid newsprint and inexpensive yellow tablet paper as these deteriorate quickly. Photocopy newspaper articles onto archival quality paper. “Permalife” paper is a brand that is acceptable. Lamination or dry-mounting is not recommended. Black and white photographs last longer than color ones, so these are pr eferable. Those on If color is important, make fiber-based paper last the longest. color photocopies in a stable format such as those provided by Epson color printers. may explode from trapped gases emitted during microbial Avoid canned foodstuffs as they surrounding items permanently. Fr eeze-dried foods sealed breakdown of the food and stain completely in impermeable packaging are preferable. Don’t use pressure sensitive tapes or adhesives of any kind for wrapping items or sealing envelopes, because these c an stain other items. PVC (polyvinyl chloride), vinyl sheeting, natur al rubber, or polyurethane foam may deteriorate quickly over time and release gases that can ha rm other materials in the capsule space. These materials are commonly found in toys, do lls, and other objects. If you select these items, isolate them from the other items in the capsule. Minnesota Historical Society – revised 2010 Page 1 of 3

2 Avoid wool, silk and nylon fabrics, if possible. Wool and silk contain sulphur that can tarnish metals. Nylon deteriorates relatively quickly over time. materials or chemicals in the capsule. Don’t place loaded ammunition or other explosive eptable, but isolate them so t hat lubricants cannot seep out and Unloaded weapons are acc stain other objects. How to Protect Items in the Capsule Some items are fragile and need to be wrapped or otherwise protected for long term storage in the capsule. If flowers are to be placed in the capsule, freeze-dry or press them and place into a polyethylene bag. Polyethylene zip lock closure bags are the best to use as they are stable. They can be found in grocery stores, but check the box to be sure that the plastic is made of polyethylene only. Items that are not in individual bags or other containers shoul d not touch each other in the capsule in order to eliminate color transfer and the migration of acids and other chemicals from poor quality paper. Place all natural and paper items in polyeth ylene bags or polyester film enclosures. able and can be used to protect photo and paper Polypropylene plastic is also very st enclosures. Polyester clear film is very stable and also can be used to protect papers and photos. Interleave between posters and maps or other fl at items in the same bag or enclosure with acid-free tissue. Use unbuffered MicroChamber or ArtCare papers and boards for black and white photographs and protein-based materials. Wrap textiles in polyester film an d tie with un-colored cotton twill tape. e crumpled pieces of acid-free tissue in the fold to prevent When folding clothing items, plac sharp creasing and broken threads. Place coins and other metal objects in a ta rnish-reducing enclosure such as Corrosion Intercept film or polyethylene/po lypropylene coin holders. Tarnis h-inhibiting papers and cloths should be avoided as the inhibitors are volat ile organic chemicals and may dissolve plastics and harm other materials in the capsule. Place items in enclosures such as Corrosion In tercept or Static Inte rcept film bags. Oxygen absorbers such as Ageless or RP may be used to further prevent ox idation of sensitive ng with other supplies from Keepsafe Systems). surfaces (available alo Minnesota Historical Society – revised 2010 Page 2 of 3

3 Place the heaviest objects on the bottom of the capsule. Use only a soft pencil to label items rather than ink, ink pens or felt-tip markers. Do not use stick-on labels. crumpled acid-free tissue paper to prevent Fill any empty spaces around the items with shifting. Don’t use plastic packi ng materials, especially bubble pa ck. It is best to avoid the starch-based packing “peanuts” , as they are not made for long term use. The interior of the capsule, as a rule, shoul d be conditioned to 20%-25% relative humidity. Desiccant silica gel may be used in individual enclosures for materials such as metals and and other organic materials require a minimal level of electronic components, but paper moisture to avoid extreme embrittlement and deter ioration. Silica gel crystals in canisters or to 20%-25% and sealed until ready for use, sheet form (ArtSorb panels) should be conditioned then placed inside the capsule housing immediat ely before sealing. One ounce of gel should be used for every cubic foot of air inside the capsule. Where to find and order the packing materials mentioned NOTE: The following list is provided for informational purposes only and is not an MHS endorsement of any particular vendors or sources. KeepSafe, Inc. Distributor of archival and long-term preservation supplies and equipment: . University Products, Inc. Complete archival and collector’s preservation supplies: . rmation, supplies and equipment Future Packaging, Inc. Complete time capsule info distributor: . Scrapbook supplies, bags, photo Grocery stores and large discount retailers: sleeves. Minnesota Historical Society – revised 2010 Page 3 of 3

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