For weekly cleaning of porcelain enamel, dishwashing detergent and hot water work well at cleaning the surface. The detergent helps to cut through the grease. For a more deep cleaning, use baking soda and ammonia and a gentle sponge.
Porcelain enamel does best when it gets regular cleaning on a weekly basis. For these frequent cleanings, don’t use harsh chemicals or anything abrasive. All that is needed is a bucket of hot water and dishwashing detergent, and a soft sponge or rag. Dip the rag into the soapy water, and wash the porcelain enamel fixture. Rinse the soap well.
About once a month or for deep cleaning, it is okay to add some ammonia and baking soda to the cleaning regimen. This helps remove some stains and provide a deeper clean. Baking soda is mild enough to be used as an abrasive material that cleans dirt and grime without scratching the surface. Add warm water, 1/4 cup of ammonia and 1/4 cup of baking soda in a bucket. Use a soft sponge to scrub the porcelain with this cleaning mixture, rinsing it well.
Additional stains can be removed by using table salt and lemon juice. This often works better than baking soda at removing stubborn stains.