--- a/blockproc/java/Makefile
+++ b/blockproc/java/Makefile
@@ -9,8 +9,10 @@
 	$(JC) $(FLAGS) net/sourceforge/ltfat/*.java net/sourceforge/ltfat/thirdparty/*.java
 	jar cf blockproc.jar net/sourceforge/ltfat/*.class net/sourceforge/ltfat/thirdparty/*.class
 
-clean:
-	$(RM) net/sourceforge/ltfat/*.class
-	$(RM) net/sourceforge/ltfat/thirdparty/*.class
+clean: classclean
 	$(RM)  *.jar
 
+classclean:
+	$(RM) net$(PS)sourceforge$(PS)ltfat$(PS)*.class
+	$(RM) net$(PS)sourceforge$(PS)ltfat$(PS)thirdparty$(PS)*.class
+