Texas Instruments 4000M - Manual (Page 97)

Cleaning the Computer
Regularly take the time to check your computer and clean the screen, keyboard,
and case to ensure trouble-free computing.
Caution: Never use alcohol, benzine, thinner, or other strong chemical
agents that could damage the computer's case, and never apply liquid
directly to the computer, only to a clean cloth. Never spray cleaning fluid
or any liquid directly onto the case or screen.
Keep the case of the computer free of dust. Apply a small amount of "Id liquid
cleaner to a dry lint-free cloth, and wipe the case with the cloth.
The surface of the screen is covered with a protective plastic film that may
become smeared and accumulate dust during use. Avoid touching the screen
with your fingers.
Clean the screen regularly by applying a small amount of a diluted neutral
detergent to a dry, lint-free cloth. Gently rub the surface of the screen with the
cloth.
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