Not sure about corrosion - this came from Conair's site on Decalcifying the bigger unit - I would assume it would work on the smaller one;
DECALCIFICATION
If the appliance begins to produce steam more slowly than usual or stops producing steam and then starts again, or if the low water indicator lamp illuminates even with water container full, you may need to decalcify your steamer.
Decalcification refers to removing the calcium deposits which form over time on the metal parts of the steamer. For best performance from the Conair Fabric Steamer, decalcify the unit from time to time. The frequency depends upon the hardness of your tap water and how often you use the steamer.
To decalcify use a solution of 1/3 white vinegar and 2/3 water in the water container. Replace the water container into the unit. Plug the unit into electrical outlet. Turn to the ON position and run until half the amount has steamed (1 LITER). Turn the unit to the OFF position, unplug from electrical outlet, and allow to sit for 30 minutes. Remove water container.
Remove excess water from the reservoir by lifting the unit, inverting, and pouring the unit over sink, and allowing water to drain from internal reservoir. Repeat the above procedure as many times as necessary until a normal steam rate returns, usually 2 to 3 times. With each repeated cycle, use a fresh solution of vinegar and water. Run one cycle of fresh, cold water through the unit at the completion of decalcification, before using the unit again to steam garments.