Sans the writings, this brown envelope should still be good enough to use. However, there is a possibility that the last recipient will no longer use it given that it's no longer pleasing to look at.
So in accordance to the green initiatives in the office, we decided to give this used envelope a little face lift. We designed a label that is easy to print from its .pdf format. (Printing on the other side of a used paper is preferred.)
A sender will just have to write the delivery details on one box. Upon receipt, the recipient has to cross out the same box and write on the other for the next correspondence. This is so spontaneous that this brown envelope can now be routed within the office for up to 34 times.