Other than that, I imagine it would be relatively easy to go from someone reuse for artistic or craft. (You may want to delete any personal identification marks the first.) There are a number for sale on eBay (in the collectibles or section of Science mostly), but if you want to get into that, you can give the waste locally on Freecycle or Gumtree / List of Craig 's.
Does anyone have any specific suggestions for things to do with them?