diff --git a/glafp-utils/sgmlverb/Makefile b/glafp-utils/sgmlverb/Makefile
index 9d47c267968c3657372a5a31164b13d0a4cb35a4..dc0eccae475003418f3d5b2980d5070f8c362707 100644
--- a/glafp-utils/sgmlverb/Makefile
+++ b/glafp-utils/sgmlverb/Makefile
@@ -7,6 +7,8 @@ LIBS = $(FLEX_LIB)
 
 override SRC_FLEX_OPTS=-8
 
+CLEAN_FILES += sgmlverb.c
+
 #
 # For src distributions, include flex output.
 #