The list of materials given by Tony Clayton as having been used in making coins and medals is extensive and fascinating, but I've got a few possible add-ons, particularly where medals are concerned...I can even offer some attached scans as "proof"

Wood is used for many medals, and even for wooden nickels (17th Century German medal of an unknown man)

Then, too, there's sawdust, mixed (it is said) with blood to form Bois Durci (19th Century French medal of Abee L'Epee)

Medals are also pressed into Horn (Pope athanasius)

A Russian mining medal of the 60s incorporates Germanium among other metals

Another Russian medal of 1961 to celebrate German Titov's flight is made of Rocket nose-cone material

Maybe it's not a medal, though it sure looks like one, and it's made of 19th Century French laundry Soap

Also, there's a category of souvenir medals made of Lava (from Vesuvius in 1843)

Finally there are edible medals which, while covered in gold foil, are really Chocolate (for Hanukkah)

And even drinkable currency, namely pre-Russian Revolutionary pressed Tea Bricks which in whole or part circulated as money in Mongolia and China.

To view a slide show of Ira's images, see:www.flickr.com/photos/coinbooks/sets/72157625160375603/show/

To read the earlier E-Sylum article, see:FEATURED WEB SITE: METALS USED IN COINS AND MEDALS(www.coinbooks.org/esylum_v13n43a29.html)