Nikon D300 Complete Manual page 697

the cleaning has been completed.
6. This is a good time to decide how you want this
automatic sensor cleaning to be performed in the
future (the default is Cleaning off). Use the Direction
pad to navigate to the Clean at startup/shutdown
option and press the > key to select it.
7. I personally prefer Clean at shutdown, but if you're
in dusty conditions, consider using Clean at startup
& shutdown instead. Use the Direction pad to
navigate to your choice and press the > key to select
it.
If the above method doesn't remove all the dust, you'll
õ
have to use a more aggressive and intrusive method to clean
Thom Hogan's Complete Guide to the Nikon D300
V1.02
Page 697