diff --git a/slides/makefile b/slides/makefile
index 4c91bc6..f884eb0 100644
--- a/slides/makefile
+++ b/slides/makefile
@@ -9,6 +9,9 @@ pandoc = \
 
 all: slides.pdf handout.pdf
 
+clean:
+	rm *.pdf
+
 slides.pdf: $(slides) | images
 	$(call pandoc, $^, $@)