I have been saving selvage edges from my projects for almost a year now. I only keep about an 1.5 X 8 inch piece with the printed manufacturer info. I will be making a tote when I get enough and think it will be fun to have a remembrance of what I accomplished over time. A friend of mine gave me all of hers too- so thanks for the suggestion of the mug rug. After reading this, I think all of my selvages will be repurposed.
Moda Bakeshop has a selvage pillow tutorial and there a lot of selvage ideas- just Google it.
http://www.modabakeshop.com/2009/03/selvage-pillow.html