texture and location, it could have several possible causes.
Could It Be Expanding Foam?
Yes. Construction and expanding foam products are commonly used to seal gaps and can occasionally protrude through openings. Once hardened, they can become quite firm.
Should I Scrape It Off?
Not until you have a reasonable idea of what it is. If you’re unsure, photograph it first and consider having it identified.
Is a Crunchy Texture a Sign of Mold?
Not necessarily. A hard or brittle texture can point toward dried material or hardened construction products
