I used the Path Tool .
To create a path,
around the icon's outer perimeter.

First add an Alpha Channel to the image.
Go to: Layer > Transparency > Add alpha channel.


Make a selection from this path.
Using the Path to Selection icon seen in the screenshot below.


Inverted the selection,
by going to: Select > Invert.
Then cleared the unwanted outer brown portion of the image.




This is only one of many ways this can be done.
It can also be done using a Layer Mask.