For soft scale deposits on the inside of the tubes of a seawater-cooled shell-and-tube heat exchanger, what is typically the preferred method of cleaning?

Correct Answer: Option B — Mechanical cleaning with specially designed brushes and/or flushing with hot freshwater.

Soft scale deposits are effectively removed using mechanical brushes or high-pressure hot freshwater flushing. These methods are non-abrasive and preserve the integrity of the tube walls. Using harsh chemicals or aggressive reamers is unnecessary for soft deposits and may cause premature thinning of the tube material.