Originally Posted by
pinworm
Keep all your receipts in a single location, input them as quickly as you can.
+1
Using the camera in your cell, pda, etc is a quick way to make a backup copy, if paperwork is essential.
Emailing a facsimile of the real receipt can sometimes start whomever handles travel reimbursement working on the paperwork, assuming they are willing to do this. YMMV.