When you look closely at both pages they have stains on them. I believe the stains were on the pages before the poem was typed onto them as some of the carbon smudge is on top of the stains in one spot. Another reason why I believe the stains were first on the paper as they appear inside the folds of the paper (when the pages are folded you can not see any stains), also the stains are not mirrored, so the paper must have been flat when they got the stains.