Strangely enough, the same material that's used to make melamine countertops and dishware is used in formulating the cleaning "erasers" that have become so popular. It stands to reason that melamine is a highly stain-resistant product. However, melamine is not stain-proof and will occasionally require some cleaning and stain removal. There are some easy step to ensure your melamine surfaces remain stain-free for years to come.
Dampen your cleaning eraser with clean water and rub the stains in a circular motion. Rinse the item well and allow to dry completely.
Repeat Step 1 if you see progress in the stain's removal. Continue scrubbing with the cleaning eraser until the stain dissipates entirely. If the stain persists, try Oxalic acid. Oxalic acid is a powder that can be purchased at most hardware stores.
Sprinkle the stain with a small amount of Oxalic acid. Use a toothbrush to scrub the stain using small circular motions.
Rinse well and allow to dry completely. Repeat Step 3 if necessary. Dispose of the toothbrush.
Avoid allowing Oxalic acid to make contact with your skin or eyes; the product contains irritants that can cause discomfort.