Blackened glass on stove?

[fatboise]

Recently put in a solid fuel stove (Nestor Martin RH33) but the glass door keeps blackening when the fire is on. Has anybody out there got one of these stoves and could they let me know how they find it or does anybody know how I can prevent the glass from blackening???

Is "Blackening" a real word???

 

[Kelmar]

I have a Jotul wood burning stove and this happens from time to time. However if you get a good fire going (ie one that is very hot!) it burns the black away