I thought Kasenit was banned nowadays due to the poisonous fumes, as it contains potassium ferro cyanide. Or is it difficult to get hold of as everyone stays away from the word cyanide on the MSDS sheets?
I certainly have at our training centre but I don't know if it is banned in reality or just avoided due to the hassle on the COSHH register.
Never did me any harm at school in metalwork.
Then again I couldn't sniff a whole tin.
I have heard of other similar products that are mainly carbon based and some hobby engineers using charcoal for aquariums.