FORD 2002 Focus v.2 - Manual (Page 271)

Maintenance and Specifications
271
If you see any corrosion on the
battery cables or terminals, remove
the cables from the terminals and
clean with a wire brush. You can
neutralize the acid with a solution
of baking soda and water. Reinstall
the cables when you are done
cleaning them.
If your battery has a
cover/shield, make sure it is
reinstalled after the battery has
been cleaned or replaced.
Batteries normally produce
explosive gases which can
cause personal injury. Therefore,
do not allow flames, sparks or
lighted substances to come near
the battery. When working near
the battery, always shield your
face and protect your eyes.
Always provide proper
ventilation.