I thought that I'd share how I store all of my scraps of card stock. This is a binder of just Stampin Up! scraps but you can make one of these for each of your paper types.
I start with the Stampin up! round tab punch
When I get a scrap, I punch out that color and staple it to a page protector (found at staples)
Then I add it to a binder that you can organize any way that's easy for you
I then found the RGB color codes for the current SU colors online and slid it under the clear binder cover
This method works wonderful for me and I don't have any wasted scraps anymore.