"Because no organic materials survived in the Hoxne hoard, radiocarbon can’t be used as a dating technique. Instead, archaeologists use the age of coins, which they arrive it by looking at inscriptions on the coin as well as the ruler depicted on its face.
Then farther down into the article we have this:
Surrounding the coins and gold objects were nails, hinges, locks, scraps of wood, bone and ivory. Some of the objects were packed with straw, while others were placed in smaller, leather-lined wood boxes.
Must be the box would have been preferred for the RC testing, and the rest of the stuff regarded as too precious to consume in the process.
[snip] The find was in such great condition that even fragments of textile and decorative bone were found, which had amazingly lasted for over 1,500 years! The hoard had been buried in a wooden box which had long since rotted away but archaeologists worked so carefully that they were still able to tell the way the objects had been packed... There were toiletry implements, which include toothpicks, small implements probably used to clean the ears or removing cosmetics from small containers. There is also a niello gilded pair of objects in the form of ibises which were used again as toothpicks. There are three other objects which probably contained brushes for cosmetics and creams. [/snip]
http://www.hoxne.net/history/hoard.html