diff --git a/FlatCAMObj.py b/FlatCAMObj.py
index 96ce05c4..1400727b 100644
--- a/FlatCAMObj.py
+++ b/FlatCAMObj.py
@@ -1308,14 +1308,18 @@ class FlatCAMGeometry(FlatCAMObj, Geometry):
             #assert isinstance(app_obj, App)
 
             if self.options["paintmethod"] == "seed":
+                # Type(cp) == FlatCAMRTreeStorage | None
                 cp = self.clear_polygon2(poly.buffer(-self.options["paintmargin"]),
                                          tooldia, overlap=overlap)
 
             else:
+                # Type(cp) == FlatCAMRTreeStorage | None
                 cp = self.clear_polygon(poly.buffer(-self.options["paintmargin"]),
                                         tooldia, overlap=overlap)
 
-            geo_obj.solid_geometry = list(cp.get_objects())
+            if cp is not None:
+                geo_obj.solid_geometry = list(cp.get_objects())
+
             geo_obj.options["cnctooldia"] = tooldia
 
             # Experimental...
@@ -1347,6 +1351,9 @@ class FlatCAMGeometry(FlatCAMObj, Geometry):
 
         name = outname or self.options["name"] + "_paint"
 
+        # This is a recursive generator of individual Polygons.
+        # Note: Double check correct implementation. Might exit
+        #       early if it finds something that is not a Polygon?
         def recurse(geo):
             try:
                 for subg in geo:
@@ -1368,14 +1375,17 @@ class FlatCAMGeometry(FlatCAMObj, Geometry):
             for poly in recurse(self.solid_geometry):
 
                 if self.options["paintmethod"] == "seed":
+                    # Type(cp) == FlatCAMRTreeStorage | None
                     cp = self.clear_polygon2(poly.buffer(-self.options["paintmargin"]),
                                              tooldia, overlap=overlap)
 
                 else:
+                    # Type(cp) == FlatCAMRTreeStorage | None
                     cp = self.clear_polygon(poly.buffer(-self.options["paintmargin"]),
                                             tooldia, overlap=overlap)
 
-                geo_obj.solid_geometry += list(cp.get_objects())
+                if cp is not None:
+                    geo_obj.solid_geometry += list(cp.get_objects())
 
             geo_obj.options["cnctooldia"] = tooldia
 
@@ -1391,6 +1401,7 @@ class FlatCAMGeometry(FlatCAMObj, Geometry):
                 app_obj.new_object("geometry", name, gen_paintarea)
             except Exception as e:
                 proc.done()
+                traceback.print_stack()
                 raise e
             proc.done()
 
diff --git a/camlib.py b/camlib.py
index 86186c30..40586260 100644
--- a/camlib.py
+++ b/camlib.py
@@ -501,7 +501,12 @@ class Geometry(object):
         geoms.get_points = get_pts
 
         # Can only result in a Polygon or MultiPolygon
+        # NOTE: The resulting polygon can be "empty".
         current = polygon.buffer(-tooldia / 2.0)
+        if current.area == 0:
+            # Otherwise, trying to to insert current.exterior == None
+            # into the FlatCAMStorage will fail.
+            return None
 
         # current can be a MultiPolygon
         try:
@@ -559,6 +564,7 @@ class Geometry(object):
         :param seedpoint: Shapely.geometry.Point or None
         :param overlap: Tool fraction overlap bewteen passes
         :return: List of toolpaths covering polygon.
+        :rtype: FlatCAMRTreeStorage | None
         """
 
         log.debug("camlib.clear_polygon2()")
@@ -652,6 +658,8 @@ class Geometry(object):
         :type storage: FlatCAMRTreeStorage
         :param boundary: Polygon defining the limits of the paintable area.
         :type boundary: Polygon
+        :param tooldia: Tool diameter.
+        :rtype tooldia: float
         :param max_walk: Maximum allowable distance without lifting tool.
         :type max_walk: float or None
         :return: Optimized geometry.
@@ -744,6 +752,8 @@ class Geometry(object):
         Simplifies paths in the FlatCAMRTreeStorage storage by
         connecting paths that touch on their enpoints.
 
+        :param storage: Storage containing the initial paths.
+        :rtype storage: FlatCAMRTreeStorage
         :return: Simplified storage.
         :rtype: FlatCAMRTreeStorage
         """