The remarks written on the last page of the Voynich manuscript (fol 116v) puzzle the researchers for a century now.
Part of the mystery is about to be lifted today. The second word appear to spell "limon (the first letter is the Greek Lambda -uppercase Λ, lowercase λ ). It looks like the author of the remark is listing the positions (the third word spells something like pociicii) of the lemon juice written text in the manuscript. That explains why there are so many burn marks in the book that is otherwise so well preserved.
In case you wonder, the lemon juice invisible ink trick does work on parchment even better than on paper, because the animal skin is not wrinkled as easily by the liquid "ink".
I personally belive there is no lemon ink in the Voynich manuscript, however, somebody had the opportunity to search for it and unfortunately destroyed parts of the manuscript.