In my experience, using a pumice stone on old porcelain surfaces is a game-changer when dealing with stubborn stains like mineral deposits and rust. What I found particularly helpful is to first ensure the pumice stone and the porcelain surface are thoroughly wet before starting. This reduces the risk of scratching while allowing the stone to gently scour away tough buildup. Many people overlook the durability of older porcelain fixtures, assuming they are too fragile for abrasive cleaning, but in truth, their thickness provides a buffer that lets the pumice stone work its magic safely. It's important to apply light pressure and use smooth, circular motions to avoid damaging the surface. I've also noticed that this method not only improves the appearance of toilets, sinks, and tubs but also helps maintain better hygiene by preventing the accumulation of bacteria in hard-to-clean stains. Regular maintenance with a pumice stone can extend the life of your fixtures and reduce the need for harsh chemical cleaners. A tip I’d add is to rinse the area well after scouring and dry it with a soft cloth to prevent water spots. Over time, combining this approach with proper porcelain care keeps your bathroom fixtures looking almost new and cuts down on plumbing issues related to mineral clogging. Always test a small inconspicuous area first to confirm no unwanted marks occur. Overall, the pumice stone is an eco-friendly, budget-friendly, and practical solution for porcelain care that every homeowner should consider trying.