Arches Aquarelle and that nasty black goo

[buze]

I like that paper, but the black 'glue' on the border of the paper get detached in the water and can even stain the paper itself if rubbed.

Does anyone has a way to remove it cleanly, short of re-cutting the paper ?

 

[nawagi]

Re-cut a CH off each edge- a pain, but that's what I do.