diff --git a/configure_dialog.py b/configure_dialog.py
index 8b143a9..bfaf5ff 100644
--- a/configure_dialog.py
+++ b/configure_dialog.py
@@ -1,18 +1,12 @@
 from __future__ import print_function
 from future.builtins import super
 
-import os
-import sys
 import numpy
-import matplotlib
-from matplotlib.figure import Figure
-from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg
-from PyQt5.QtGui import QIcon, QFont
+from PyQt5.QtGui import QFont
 from PyQt5.QtCore import Qt
-from PyQt5.QtWidgets import QSizePolicy, QMainWindow, QApplication, QAction
-from PyQt5.QtWidgets import QMenu, QWidget, QVBoxLayout, QMessageBox
-from PyQt5.QtWidgets import QSlider, QHBoxLayout, QLabel, QDialog, QPushButton
-from PyQt5.QtWidgets import QDialogButtonBox, QGridLayout, QRadioButton, QLineEdit
+from PyQt5.QtWidgets import QHBoxLayout, QVBoxLayout, QMessageBox, QLabel
+from PyQt5.QtWidgets import QDialog, QPushButton, QRadioButton
+from PyQt5.QtWidgets import QGridLayout, QLineEdit
 
 
 class ConfigureMeassurementDialog(QDialog):
diff --git a/figure_canvas.py b/figure_canvas.py
index 42193e5..17a0922 100644
--- a/figure_canvas.py
+++ b/figure_canvas.py
@@ -1,18 +1,9 @@
 from __future__ import print_function
 from future.builtins import super
 
-import os
-import sys
-import numpy
-import matplotlib
 from matplotlib.figure import Figure
 from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg
-from PyQt5.QtGui import QIcon
-from PyQt5.QtCore import Qt
-from PyQt5.QtWidgets import QSizePolicy, QMainWindow, QApplication, QAction
-from PyQt5.QtWidgets import QMenu, QWidget, QVBoxLayout, QMessageBox
-from PyQt5.QtWidgets import QSlider, QHBoxLayout, QLabel, QDialog
-from PyQt5.QtWidgets import QDialogButtonBox
+from PyQt5.QtWidgets import QSizePolicy
 
 
 class GravityModelCanvas(FigureCanvasQTAgg):
diff --git a/interactive.py b/interactive.py
index 8cdfaf8..0e5215c 100644
--- a/interactive.py
+++ b/interactive.py
@@ -1,26 +1,12 @@
 from __future__ import division, absolute_import
 from future.builtins import super, zip
 
-try:
-    import cPickle as pickle
-except ImportError:
-    import pickle
-
-import os
-import sys
 import numpy
-import matplotlib
-from matplotlib import pyplot, widgets, patches
+from matplotlib import pyplot, patches
 from matplotlib.lines import Line2D
 from matplotlib.figure import Figure
 from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg
-from PyQt5.QtGui import QIcon
 from PyQt5.QtCore import Qt, pyqtSignal
-from PyQt5.QtWidgets import QSizePolicy, QMainWindow, QApplication, QAction
-from PyQt5.QtWidgets import QMenu, QWidget, QVBoxLayout, QMessageBox
-from PyQt5.QtWidgets import QSlider, QHBoxLayout, QLabel, QDialog
-from PyQt5.QtWidgets import QDialogButtonBox
-
 
 from fatiando import utils
 from fatiando.gravmag import talwani
diff --git a/moulder.py b/moulder.py
index dbf86a8..49a325c 100644
--- a/moulder.py
+++ b/moulder.py
@@ -1,21 +1,15 @@
 from __future__ import print_function, division
 from future.builtins import super
 
-import os
 import sys
 import numpy
-import matplotlib
-from matplotlib.figure import Figure
-from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg
 from matplotlib.backends.backend_qt5 import NavigationToolbar2QT
 from PyQt5.QtGui import QIcon
 from PyQt5.QtCore import Qt
-from PyQt5.QtWidgets import QSizePolicy, QMainWindow, QApplication, QAction
-from PyQt5.QtWidgets import QMenu, QWidget, QVBoxLayout, QMessageBox
-from PyQt5.QtWidgets import QSlider, QHBoxLayout, QLabel, QDialog
-from PyQt5.QtWidgets import QDialogButtonBox, QDoubleSpinBox
+from PyQt5.QtWidgets import QMainWindow, QApplication, QAction
+from PyQt5.QtWidgets import QWidget, QVBoxLayout, QMessageBox, QDoubleSpinBox
+from PyQt5.QtWidgets import QSlider, QLabel
 
-from figure_canvas import GravityModelCanvas
 from double_slider import QDoubleSlider
 from interactive import Moulder
 from configure_dialog import ConfigureMeassurementDialog
@@ -77,7 +71,7 @@ class MoulderApp(QMainWindow):
 
     def _define_actions(self):
         self.configure_action = QAction(QIcon.fromTheme('preferences-system'),
-                                  '&Configure...', self)
+                                        '&Configure...', self)
         self.open_action = QAction(QIcon.fromTheme('document-open'),
                                    '&Open model', self)
         self.open_action.setShortcut('Ctrl+O')
@@ -92,7 +86,7 @@ class MoulderApp(QMainWindow):
         self.quit_action.setShortcut('Ctrl+Q')
         self.about_action = QAction("&About", self)
         self.new_polygon_action = QAction(QIcon.fromTheme("list-add"),
-                                             "&New Polygon", self)
+                                          "&New Polygon", self)
         self.delete_polygon_action = QAction(QIcon.fromTheme("list-remove"),
                                              "&Delete Polygon", self)
         self.add_vertex_action = QAction(QIcon.fromTheme("document-new"),