Spots on book fore edge

I received this book this morning, and can see that there are some spots on the fore edge pages. How do I remove these? Any suggestions?

Just replied to you on the FSD group.
In brief, try sodium borohydride on the affected area. Paper does not have to be rinsed after treatment.

Full article here: https://blog.bookstellyouwhy.com/bid/230209/how-to-prevent-and-reverse-foxing-in...

There is always sandpaper though,
https://www.youtube.com/watch?v=oTQRx0iv5q4

Edited to add:
There appears to be a similar spot on the edge of the board. Look a little higher than a third of the way from the bottom of the 1st picture on the left edge of the blue cover. Perhaps you could try to wipe or treat this spot depending on the material of the board cover before moving on to the page edges.

It could be fly (or some other insect) poop. In the larger spots you can see the central speck from which the stain is spreading. Treatment for the stains may be the same as for foxing, but I'd start by removing the poop with a brush or brush+vacuum.

There are some tips on removing roach excrement stains from books here: https://penandthepad.com/remove-roach-excrement-stains-books-5647679.html

>3 bookist: I’ll try to vacuum and see what happens but I don’t think it’s insect dropping as I’ve already tried to wipe with a kitchen roll paper.

>2 mr.philistine: thanks. I will see where I can get that but sandpaper might just work.

I'd use a superfine sandpaper and treat the entire fore edge for uniformity.

>5 ironjaw: Not sure how your spot removal project is coming along. But here are a few more paper cleaning supplies that might be of interest.
https://www.preservationequipment.com/Catalogue/Cleaning-Products/Paper-Cleaning

and some micro-fibre cloths and sponges..
https://www.preservationequipment.com/Catalogue/Cleaning-Products/Sponges-Cloths

>7 mr.philistine: thanks. I haven’t bought any supplies. Didn’t get fine sandpaper but have too. I’ve been looking through some of my books and some have spotting and some paperbacks are foxed so I’m not sure what to with them. I dislike throwing books out but have thought of I should give them to Oxfam. It’s my fault really, I didn’t have space and stored my books in a large plastic boxes in the loft. 9 out 10 books have come just fine. Living in an apartment doesn’t make it easier and it’s just now that I’ve been able to acquire more bookshelves to have the necessary space. I feel ao guilty but didn’t have a choice.

If you think there is something wrong with the books, please throw them away and DO NOT pass damaged books on.

>9 MarthaJeanne: Not everybody, unlike most (?) LT members, keeps books for ever. I'm sure read and discard is more usual. Sending a foxed book to Oxfam should be fine.
In fact, in my experience they often charge more for foxed books ('cause they're old!)

Obviously there is a line to be drawn, frank fungus, wet rot, etc. ;-)

I finally got hold of fine sandpaper and will give it a go. I know I’ve zoomed in closely in the pictures to show the spots but they are tiny compared to the size of the book. I’ll see this evening how I fare. There’s not foxing or smell and it doesn’t seem to be spreading.