How corrosion can be removed?

There are many ways to remove corrosion from system. But correct approach depends on the type and reason of corrosion.

1- Cut off the connection of environment with substrate by any coating system.

2- Make a system which forces your substrate to act as cathode by connecting it with the material higher in EMF series or by providing external potential.

3- Decrease the corrosivity of environment by normalizing its PH. 

There are two methods to prevent the corrosion:

1. Sacrificial anode

2. Impress current