Apple PC Compatibility Card - Manual (Page 89)

5 Touch the metal on the bottom of the computer.
Always do this before you touch any parts, or install any components, inside
the computer. Touching the metal helps release static electricity from your
body and prevent possible damage to internal components.
IMPORTANT You can collect static electricity just by walking away from and
then back to your computer. If you need to move away from your computer
during installation, remember to touch the metal bottom again before you
continue installing.
89 Installing the Card in a Power Macintosh 8600 or 9600