What to make of the big stain on f116v

[Zauriek]

But it seems also possible that the book was upright and the water flowed into the spaces between the last page (which is not flat) and the back cover.

Well i think the weight of the book was pressing down the last page against the "fazzoletto" or some squarish fabric due the push upward effect on the rectangle,  the cleaner square imprit looks like a mountain emerging over the page.
   

The vellum may have been permeable to oily ("non-polar") liquids. 

Oh, that is beyond my understanding, i would take it as you say until i learn something new. Is interesting.

No sign of wiping below the line (B), agreed.  But what above it? 

yea, visually it not so clear as the bottom part. It could be wiped. But is weird that it wiped up only upwards in a certain angle. The fold*1 and this border 2* indicates no wiping to me, but i am not expert.
   

We are all amateurs when it comes to the VMS...

Thanks; i know there are some harcore researchers on the forum so it is somewhat intimidating. (But it is a cool feeling, like there is serious research beeing done and stuff.)