Thanks for that!
The easiest way to select a spot is to use the Lasso tool, or alternatively clicking close to their edges using the Flood Fill Darker Pixels mode and then Growing the mask globally (using the grow button) or per-blob (using the Grow Blob) brush mode.
After that, launch the Heal module, which will use the mask you give it to heal out the pixels selected.
Hope this helps!
StarTools creator and astronomy enthusiast