Skoda FABIA Owner's Manual page 181

180 Taking care of your vehicle and cleaning the vehicle
WARNING
The seat belts must not be removed for cleaning.
Never clean the seat belts chemically as dry cleaning may destroy the
fabric. The seat belts must also not be allowed to come into contact with
corrosive liquids (such as acids etc.).
Seat belts which have damage to the webbing, the connections, the
inertia reel or the lock should be replaced by a specialist garage.
Inertia reel belts must be completely dried before being reeled up.