My wax stamp/sealing wax spoon is changing color
Edited
Your wax stamp and or sealing wax spoon is likely developing a patina. This is a natural aging process of solid brass and will not affect the quality of wax seal your stamp creates. If you want to keep your wax stamp looking brand new, you can remove the patina using a brass jewelry cleaner. Look for a cleaner that doesn't contain abrasives as they can ruin the quality of the engraving.