diff --git a/make/lilypond.mk b/make/lilypond.mk
index c9980c31..992a853c 100644
--- a/make/lilypond.mk
+++ b/make/lilypond.mk
@@ -6,9 +6,19 @@ clean: clean.lilypond
 view: $(LY_PDF)
 	kpdf $<
 
+convert: convert.done
+
 %.pdf: %.ly
 	lilypond $<
 
 clean.lilypond:
-	rm -f *.pdf *.ps 
+	rm -f *.pdf *.ps *.done *.tmp
 
+convert.done:
+	set -e; for o in $(wildcard *.ly); do \
+		echo converting $$o ;\
+		cp $$o $$o.tmp ;\
+		convert-ly $$o.tmp ;\
+		mv $$o.tmp $$o ;\
+	done
+	touch $@