This is a wood stove in a home I am overseeing for the owners. Hoping someone can answer what this whiteish, gray substance on top surface of wood stove it? It is a very hard substance that does not come off easily. Also I believe the chimney pipe in installed incorrectly (upside down and unsealed) and hoping someone can offer advice. Thank you for your assistance.
![[Hearth.com] Build up on top off wood stove [Hearth.com] Build up on top off wood stove](https://www.hearth.com/talk/data/attachments/295/295605-236f6a48f79955d290e95525b4e4c797.jpg?hash=x3UDeCMNt9)
![[Hearth.com] Build up on top off wood stove [Hearth.com] Build up on top off wood stove](https://www.hearth.com/talk/data/attachments/295/295604-c9a0565045ec492ef0ca633d25bcd2f9.jpg?hash=bmmpqUPk1k)
![[Hearth.com] Build up on top off wood stove [Hearth.com] Build up on top off wood stove](https://www.hearth.com/talk/data/attachments/295/295605-236f6a48f79955d290e95525b4e4c797.jpg?hash=x3UDeCMNt9)