Olympus PT-018 - Manual (Page 28)

E-27
Install the O-ring.
Confirm that no foreign matter is attached, apply a thin coat of the accessory
grease to the O-ring, and fit the O-ring into the groove. At this time, confirm
that the O-ring does not stick out from the groove.
：・When a mechanical pencil or a similar other sharp object is
used to remove the O-ring or to clean the inside of the O-
ring groove, the Case and the O-ring may be damaged and
water leakage may be caused.
・When the O-ring is checked with the fingertips, take care not
to stretch the O-ring.
・Never use alcohol, thinner, benzene or similar solvents or
chemicals detergents to clean the O-ring. When such
chemicals are used, it is likely that the O-ring will be
damaged or that its deterioration will be accelerated.
CAUTION
Use a clean cloth (that doesn't shed fibers), a toothbrush, tissue paper or the
like, to remove any foreign matter from the O-ring groove. Clean the O-ring
contact surface on the front lid in the same way to remove any sand and dirt.