Welcome to SRP. Metal polish such as Semichrome, Maas, Flitz or Wenol on a Q-tip followed by a paper towel is what I do. Careful around the etching, depending on how deep it is , you may lose some. If it is gold wash metal polish will remove it in short order. Looks like 'water spots' from your photo. You have to take extra care if your water affects razors that way. Mine does with some highly polished blades and not with others. A lubricant such as Birchwood Casey RIG is great for protection of any metal surface from rust IME.