diff --git a/test/performance/org/openstreetmap/josm/data/osm/visitor/paint/AbstractMapRendererPerformanceTestParent.java b/test/performance/org/openstreetmap/josm/data/osm/visitor/paint/AbstractMapRendererPerformanceTestParent.java
index 569c6a0..63b5f74 100644
--- a/test/performance/org/openstreetmap/josm/data/osm/visitor/paint/AbstractMapRendererPerformanceTestParent.java
+++ b/test/performance/org/openstreetmap/josm/data/osm/visitor/paint/AbstractMapRendererPerformanceTestParent.java
@@ -71,6 +71,15 @@ public abstract class AbstractMapRendererPerformanceTestParent {
         }
     }
 
+    protected static void clean() throws Exception {
+        g = null;
+        img = null;
+        nc = null;
+        dsRestriction = null;
+        dsMultipolygon = null;
+        dsCity = null;
+    }
+
     protected abstract Rendering buildRenderer();
 
     protected final void test(int iterations, DataSet ds, Bounds bounds) throws Exception {
diff --git a/test/performance/org/openstreetmap/josm/data/osm/visitor/paint/StyledMapRendererPerformanceTest.java b/test/performance/org/openstreetmap/josm/data/osm/visitor/paint/StyledMapRendererPerformanceTest.java
index 018bfd0..cf7940d 100644
--- a/test/performance/org/openstreetmap/josm/data/osm/visitor/paint/StyledMapRendererPerformanceTest.java
+++ b/test/performance/org/openstreetmap/josm/data/osm/visitor/paint/StyledMapRendererPerformanceTest.java
@@ -6,6 +6,7 @@ import java.io.IOException;
 
 import javax.imageio.ImageIO;
 
+import org.junit.AfterClass;
 import org.junit.BeforeClass;
 import org.openstreetmap.josm.gui.mappaint.MapPaintStyles;
 
@@ -23,6 +24,11 @@ public class StyledMapRendererPerformanceTest extends AbstractMapRendererPerform
         MapPaintStyles.readFromPreferences();
     }
 
+    @AfterClass
+    public static void clean() throws Exception {
+        AbstractMapRendererPerformanceTestParent.clean();
+    }
+
     @Override
     protected Rendering buildRenderer() {
         return new StyledMapRenderer(g, nc, false);
diff --git a/test/performance/org/openstreetmap/josm/data/osm/visitor/paint/WireframeMapRendererPerformanceTest.java b/test/performance/org/openstreetmap/josm/data/osm/visitor/paint/WireframeMapRendererPerformanceTest.java
index 75f74d3..7549d9e 100644
--- a/test/performance/org/openstreetmap/josm/data/osm/visitor/paint/WireframeMapRendererPerformanceTest.java
+++ b/test/performance/org/openstreetmap/josm/data/osm/visitor/paint/WireframeMapRendererPerformanceTest.java
@@ -1,6 +1,7 @@
 // License: GPL. For details, see LICENSE file.
 package org.openstreetmap.josm.data.osm.visitor.paint;
 
+import org.junit.AfterClass;
 import org.junit.BeforeClass;
 
 /**
@@ -13,6 +14,11 @@ public class WireframeMapRendererPerformanceTest extends AbstractMapRendererPerf
         AbstractMapRendererPerformanceTestParent.load();
     }
 
+    @AfterClass
+    public static void clean() throws Exception {
+        AbstractMapRendererPerformanceTestParent.clean();
+    }
+
     @Override
     protected Rendering buildRenderer() {
         return new WireframeMapRenderer(g, nc, false);