I'm fond of aged paper and one of my favourite sources are old magazines and journals. I wouldn't feel good about destroying books for my paper needs like packaging, papier mache etc., but with magazines and journals it's different - huge variety of textures and shades, interesting articles you stumble upon and want to read... I love the process. By the way some these journals date back to 1950s.
To see more creative spaces hop over to kootoyoo's blog.