Lexus GS300 1998 Owner's Manual page 27

KEYS AND DOORS
11L023-3
D Do not bend the key grip.
D Do not cover the key grip with any material that cuts
off electromagnetic waves.
D Do not knock the key hard against other objects.
D Do not leave the key exposed to high temperatures for
a long period, such as on the dashboard and hood
under the direct sunlight.
D Do not put the key in water or wash it in an ultrasonic
washer.
D Do not use the key with electromagnetic materials.
14
ENGINE IMMOBILISER
SYSTEM