Trivia: What is used to scrub stains off porcelain?
Brick
Charcoal
Pumice stone
Razor blade
The correct answer is Pumice stone
So why is this answer correct? : Pumice stones are lightweight, porous volcanic stones that clean porcelain appliances such as sinks and toilets. Pumice is harder than most mineral deposits that build up on porcelain, so its tough texture will scour off otherwise difficult stains.