Bosch HSN 2522 Instruction Manual page 16

Discoloration on the hob
Examples of possible
damage
16
q The glass scaper has a sharp blade. It is best not
to use it too near the hob surround, as this could
be damaged.
Shimmering metallic discoloration may be caused by
material which has rubbed off saucepan bases, or by
unsuitable cleaning agents. These can only be
removed with some effort, using ceramic and steel
hob cleaner or "Hob Clean". Our after sales service
can remove such stains, but will make a charge.
Aggressive or harsh cleaning products could sand off
the trim and dark stains may appear. Food residues
which have been burnt on and not removed can also
cause the hob to be discolored.
They do not influence the function or stability of the
glass ceramic.
Pitting caused by melted sugar
or food with a high sugar
content.
Metallic shimmering
discoloration due to wear
from pan bases or use of an
unsuitable cleaning agent.
Scratches caused by salt,
sugar, sand or rough pan bases
Decor rubbed off due to use
of an unsuitable cleaning
agent.