Buick RIVIERA 1993 Manual page 255

Cleaning the Inside of Your Buick
Use a vacuum cleaner often to get rid of dust and loose
dirt. Wipe vinyl with a clean, damp cloth.
Your Buick dealer has two GM cleaners -- a
solvent-type spot lifter and a foam-type powdered
cleaner. They will clean normal spots and stains very
well.
Here are some cleaning tips:
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Always read the instructions on the cleaner label.
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Clean up stains as soon as you can -- before they set.
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Use a clean cloth or sponge, and change to a clean
area often. A soft brush may be used if stains are
stubborn.
Use solvent-type cleaners in a well-ventilated area
only. If you use them, don't saturate the stained area.
If a ring forms after spot cleaning, clean the entire
area immediately or it will set.