diff --git a/client.c b/client.c
index 6bd1f251e..2d1991c92 100644
--- a/client.c
+++ b/client.c
@@ -1302,11 +1302,13 @@ luaA_client_index(lua_State *L)
         if(!xutil_class_hint_get(globalconf.connection, (*c)->win, &hint))
              return 0;
         lua_pushstring(L, hint.res_class);
+        xutil_class_hint_wipe(&hint);
         break;
       case A_TK_INSTANCE:
         if(!xutil_class_hint_get(globalconf.connection, (*c)->win, &hint))
             return 0;
         lua_pushstring(L, hint.res_name);
+        xutil_class_hint_wipe(&hint);
         break;
       case A_TK_ROLE:
         if(!xutil_text_prop_get(globalconf.connection, (*c)->win,
diff --git a/common/xutil.h b/common/xutil.h
index 2766148fb..43021adc7 100644
--- a/common/xutil.h
+++ b/common/xutil.h
@@ -100,6 +100,13 @@ typedef struct
     char *res_class;
 } xutil_class_hint_t;
 
+static inline void
+xutil_class_hint_wipe(xutil_class_hint_t *c)
+{
+    p_delete(&c->res_name);
+    p_delete(&c->res_class);
+}
+
 bool xutil_class_hint_get(xcb_connection_t *, xcb_window_t, xutil_class_hint_t *);
 
 bool xutil_text_prop_get(xcb_connection_t *, xcb_window_t, xcb_atom_t, char **, ssize_t *);