To remove carbon buildup from the metal portion of a pressing comb, immerse it in a solution containing what?

The most effective choice to remove carbon buildup from the metal portion of a pressing comb is a solution of baking soda. Baking soda, or sodium bicarbonate, is a mild alkaline compound that can help to break down and lift off residue, including carbon deposits. When immersed, it reacts with the carbon buildup, making it easier to scrub away. Additionally, baking soda is a safe, non-toxic option that won't damage the metal of the comb, preserving its integrity while cleaning it.

The other options fall short in this context. Sodium hydroxide, while an effective cleaning agent, is highly caustic and can cause damage to the comb and present safety hazards if not handled properly. Hydrogen peroxide is generally used for disinfecting rather than removing carbon buildup and may not be as effective in this specific cleaning scenario. Ammonia water can also be strong and potentially damaging to certain surfaces and materials, making it less desirable as a cleaning solution for hair styling tools like pressing combs. Therefore, baking soda stands out as the safest and most effective choice for this cleaning task.