Coins or Tokens
If you have access to equipment for metalwork, create a token with your name and home town stamped on it. You can also order custom tokens online. Alternatively, purchase a roll of vintage coins to use as signature items. Although United States coins containing precious metals are quite expensive, buffalo nickels are relatively affordable to purchase in rolls. Yet, buffalo nickels are rarely seen in circulation and would be considered quite a novelty if found in a cache. Coins also have the benefit of being able to fit in very small cache containers.
Local Items
If you travel frequently, select a signature item that represents your home town in some way or is difficult to find elsewhere. For example, someone from Michigan might use miniature cars as signature items, while someone from Florida might use shells found at the beach. Someone from Hawaii might use koa wood beads.
Miniature License Plate
Create miniature license plates with information such as your name, home state and a personal symbol or emblem. If possible, have the license plates stamped with numbers signifying how many caches you have found so far, such as "This is my 30th cache."
Favorite Poem or Quote
Print your favorite poem or quote and leave it in caches to inspire future geocachers. Because items can sometimes remain in caches for months before they are removed, select a material that will not become moldy or waterlogged. If paper is the only material that you can use, laminate it for some protection from moisture.
Useful Items
Put together a small packet of items that people could potentially need while geocaching. For example, consider including items such as clean bandages, insect repellent, a compass or an emergency whistle. Do not include anything dangerous or subject to expiration, such as aspirin or other medications.