As the title says, is the aluminium foil still usable in this condition?
If you notice, there's a very obvious white portion in the center of the aluminum foil and the entire roll is like that. Usually when I buy it from the store, it is pure silver without the white line. However when I keep it for some time, this white line appears which appears to me that the foil could be "spoilt"?
May I also ask what is the name of the condition of this aluminum foil and what causes it to be like this.