Step-8

The result is a bit dark, lets improve the lighting and sharpness.

Step-9

Add patches to the statue:

Create a new layer at the top.

Select the brush provided in the link with gray color (#808080).

Set blending mode of the layer to “overlay”.

Add “Drop shadow” layer style with following properties.

Now, brush over the image for patches.

Step-10

In this final step, lets add rust leaks to the image to enhance the effect:

Import rust leak images into the scene and position them at the edges of the masked effect.

Set blending mode to “multiply”.

Mask unwanted areas of the rust leaks in the following way to get the final result.

I hope that you find this tutorial useful.