Final answer:
The statement is true; a wire wheel should not be used on soft metals like brass to prevent damage and ensure proper cleaning, softer brushes or buffing wheels designed for such metals are preferable.
Step-by-step explanation:
The statement that a wire wheel in a bench grinder should NOT be used to clean soft metal or brass parts is True. When a wire wheel is used on soft metals like brass, it can cause embedding of wire bristles, leading to surface damage on the metal piece being cleaned, and it could also lead to premature wear on the wire wheel itself.
The correct tool for cleaning such materials would be a softer brush or a buffing wheel designed for softer materials to prevent damage and ensure optimal cleaning results.