diff --git a/include/ndbuf/ndbuf.h b/include/ndbuf/ndbuf.h
index 87184f9..3795473 100644
--- a/include/ndbuf/ndbuf.h
+++ b/include/ndbuf/ndbuf.h
@@ -178,4 +178,7 @@ int ndbuf_cmp(ndbuf_t *, ndbuf_t *);
  */
 int ndbuf_memopt(ndbuf_t *);
 
+/* free in a right way: freing allocated memory during escan */
+void ndbuf_free_item(ndbuf_t *b, void *ip, size_t is);
+
 #endif /* __NDBUF_H__ */
diff --git a/ndbuf.c b/ndbuf.c
index c3deaf8..6c0f339 100644
--- a/ndbuf.c
+++ b/ndbuf.c
@@ -913,4 +913,21 @@ int ndbuf_memopt(ndbuf_t *b)
   return 0;
 }
 
+void ndbuf_free_item(ndbuf_t *b, void *ip, size_t is)
+{
+  if(!b || !ip) return;
+
+  if(__is_moless(b->flags)) return;
+
+  if(__is_usermo(b->flags)) {
+    if((b->flags & NDBUF_BURN) && (is > 0)) b->mop->zero(ip, is);
+    b->mop->free(ip);
+  } else {
+    if((b->flags & NDBUF_BURN) && (is > 0)) memset(ip, 0, is);
+    free(ip);
+  }
+
+  return;
+}
+
 #undef DEFAULT_PREALLOC_SIZE