It could be quick if you:
1- choose "select by color tool"
2- choose to perform the selection on the hue
3- click inside the area to erase (choose an average color to reduce the number of steps)
4- clear the selected part
You see that a lot but not all of the area has been removed
Repeat steps 3 and 4
If you are lucky, you have already the whole area cleared (it happened to me), otherwise repeat.
1- choose "select by color tool"
2- choose to perform the selection on the hue
3- click inside the area to erase (choose an average color to reduce the number of steps)
4- clear the selected part
You see that a lot but not all of the area has been removed
Repeat steps 3 and 4
If you are lucky, you have already the whole area cleared (it happened to me), otherwise repeat.