diff --git a/toolkit.py b/toolkit.py
index 8cb4d72445b8d02a02bdd27ae602eca5a1433fc9..51d7aaeb9bab726880cc89d85bb16581e4f2b42c 100755
--- a/toolkit.py
+++ b/toolkit.py
@@ -859,7 +859,7 @@ class ClassificationProject(object):
         if not os.path.exists(plot_dir):
             os.mkdir(plot_dir)
         fig.savefig(os.path.join(plot_dir, "var_{}.pdf".format(var_index)))
-        plt.clf()
+        plt.close(fig)
 
 
     def plot_weights(self):
@@ -868,9 +868,11 @@ class ClassificationProject(object):
         sig = self.w_train[self.y_train == 1]
         ax.hist(bkg, bins=100, color="b", alpha=0.5)
         fig.savefig(os.path.join(self.project_dir, "eventweights_bkg.pdf"))
+        plt.close(fig)
         fig, ax = plt.subplots()
         ax.hist(sig, bins=100, color="r", alpha=0.5)
         fig.savefig(os.path.join(self.project_dir, "eventweights_sig.pdf"))
+        plt.close(fig)
 
 
     def plot_ROC(self):
@@ -914,6 +916,7 @@ class ClassificationProject(object):
         ax.set_xlabel("NN output")
         fig.legend(loc='upper center', framealpha=0.5)
         fig.savefig(os.path.join(self.project_dir, "scores.pdf"))
+        plt.close(fig)
 
 
     def plot_significance(self, lumifactor=1., significanceFunction=None, plot_opts=dict(bins=50, range=(0, 1))):
@@ -964,6 +967,7 @@ class ClassificationProject(object):
         ax.set_ylabel("Significance")
         ax.legend(loc='lower center', framealpha=0.5)
         fig.savefig(os.path.join(self.project_dir, "significances.pdf"))
+        plt.close(fig)
 
 
     @property