Don't kill yourself shredding all that paper!
Get thee to your files and start sorting and purging right now and take that stuff on down to be shredded.
Tip: Bring your bathroom scale into your office to figure out when you have 5 pounds of paper. If your scale is not sensitive enough for just 5 pounds, weigh yourself first, then weigh yourself holding the box of papers.
Find out a little more here at the Staples site: http://www.staples.com/sbd/cre/programs/copyandprint/savings_central.html?cid=PS:GS:CP:CP:B:28:10605:%2Bshredding_%2Bstaples
I am not affiliated with Staples nor do I receive any compensation from them.