diff --git a/Makefile b/Makefile
index 07b41d4..8787f06 100644
--- a/Makefile
+++ b/Makefile
@@ -3,3 +3,10 @@ all :
 	(cd tools; make)
 	(cd build; make install)
 
+clean :
+	(cd build; make clean)
+
+clobber : clean
+	(cd tools; make clean)
+	(cd build; make clobber)
+
diff --git a/tools/Makefile b/tools/Makefile
index 3d50a3e..d600077 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -10,5 +10,5 @@ apout/apout:
 	(cd apout; make; rm *.o)
 
 clean:
-	rm mkfs ml
+	rm -f mkfs ml
 	(cd apout; make clean)