If you still have unused Staples 10 off 50 coupon that is supposed to be expired on 01/31/2014, it is still alive !!
I wrote about this coupon several months ago. This coupon is awesome since it offers $10 off $50 for (almost) everything at Staples and valid for both online and in-store. Originally, you can even use more than one coupons online. However, it is already fixed so now you can use only one coupon per account online regardless of the number of coupon you have.
If you are looking for one, I gave several of them away here a week ago. I am not sure whether they are still valid or not. If you want to get it by yourself, you can follow my previous instruction. Note that I am not sure whether Staples still send this Staples 10 off 50 coupon out or not.