Deleting masks
You can delete a mask from an image, or you can merge it with the underlying layer and then delete the mask layer. However, if you merge the mask with the underlying layer, you can no longer edit the mask independently from the layer.
To delete a mask
1
On the Layers palette, right-click the mask layer, and choose
Delete.
A message appears asking if you want to merge the mask with the underlying layer.
2
Choose one of the following:
•
Yes — merges the layers and deletes the mask layer
•
No — deletes the mask layer without affecting the underlying layer
You can also delete a mask by choosing Layers 
Delete.