I have noticed that in ignaberga. The rocks in matrix are very crumbly. How do i fix it? And for me its pain to prep. Like this shell in the gaps theres really hard matrix. And the black stuff that some told me was magnesium oxide. Its really hard to remove them i need to scrape it off with dental picks. Some said toothbrushes work for them. Tried it sometimes it removes them but not often. Should i just keep to scrape them off? Risk of damaging the fossil? I do have cyanoacrylate Will that help the crumbling rocks?