diff --git a/src/lcmime.c b/src/lcmime.c
index 06c3550..33e12a9 100644
--- a/src/lcmime.c
+++ b/src/lcmime.c
@@ -135,7 +135,7 @@ int lcurl_mime_set_lua(lua_State *L, lcurl_mime_t *p, lua_State *v){
 
 #define IS_NILORSTR(L, i) (lua_type(L, i) == LUA_TSTRING) || (lua_type(L, i) == LUA_TNIL)
 #define IS_TABLE(L, i) lua_type(L, i) == LUA_TTABLE
-#define IS_FALSE(L, i) (lua_type(L, i) == LUA_TBOOLEAN) && (!lua_toboolean(L, i))
+#define IS_FALSE(L, i) ((lua_type(L, i) == LUA_TBOOLEAN) && (!lua_toboolean(L, i))) || lutil_is_null(L,i)
 #define IS_OPTSTR(L, i) (IS_FALSE(L, i)) || (IS_NILORSTR(L, i))
 
 static int lutil_isarray(lua_State *L, int i){
@@ -512,13 +512,13 @@ static int lcurl_mime_part_headers(lua_State *L){
   }
   else{
     list = lcurl_util_to_slist(L, 2);
-    luaL_argcheck(L, list, 2, "array or nil expected");
+    luaL_argcheck(L, list || IS_TABLE(L, 2), 2, "array or null expected");
   }
 
   ret = curl_mime_headers(p->part, list, 1);
 
   if(ret != CURLE_OK){
-    curl_slist_free_all(list);
+    if(list) curl_slist_free_all(list);
     return lcurl_fail_ex(L, p->err_mode, LCURL_ERROR_EASY, ret);
   }
 
diff --git a/test/test_mime.lua b/test/test_mime.lua
index e7239f4..762d896 100644
--- a/test/test_mime.lua
+++ b/test/test_mime.lua
@@ -19,6 +19,8 @@ local weak_ptr, gc_collect, dump_mime_ = utils.import('weak_ptr', 'gc_collect',
 
 local GET_URL = 'http://127.0.0.1:7090/get'
 
+local null = curl.null
+
 local function is_freed(c)
   return not not string.find(tostring(c), '%(freed%)')
 end
@@ -313,6 +315,15 @@ function test_unset_name()
   assert_not_match('Content%-Disposition:.-name="test"', info)
 end
 
+function test_unset_name_by_null()
+  mime:addpart():data('hello', 'test/html', 'test'):name(null)
+
+  local info = assert_string(dump_mime(mime))
+  assert_match('\r\n\r\nhello', info)
+  assert_match('Content%-Type:%s+test/html', info)
+  assert_not_match('Content%-Disposition:.-name="test"', info)
+end
+
 function test_unset_type()
   mime:addpart():data('hello', 'test/html'):type(false)
 
@@ -321,6 +332,14 @@ function test_unset_type()
   assert_not_match('Content%-Type:%s+test/html', info)
 end
 
+function test_unset_type_by_null()
+  mime:addpart():data('hello', 'test/html'):type(null)
+
+  local info = assert_string(dump_mime(mime))
+  assert_match('\r\n\r\nhello', info)
+  assert_not_match('Content%-Type:%s+test/html', info)
+end
+
 function test_unset_headers()
   mime:addpart():data('hello', 'test/html',{
     'X-Custom-Header: hello'
@@ -331,6 +350,26 @@ function test_unset_headers()
   assert_not_match('X%-Custom%-Header:%s*hello', info)
 end
 
+function test_unset_headers_by_null()
+  mime:addpart():data('hello', 'test/html',{
+    'X-Custom-Header: hello'
+  }):headers(null)
+
+  local info = assert_string(dump_mime(mime))
+  assert_match('\r\n\r\nhello', info)
+  assert_not_match('X%-Custom%-Header:%s*hello', info)
+end
+
+function test_unset_headers_by_empty_array()
+  mime:addpart():data('hello', 'test/html',{
+    'X-Custom-Header: hello'
+  }):headers({})
+
+  local info = assert_string(dump_mime(mime))
+  assert_match('\r\n\r\nhello', info)
+  assert_not_match('X%-Custom%-Header:%s*hello', info)
+end
+
 function test_unset_data()
   mime:addpart():data('hello', 'test/html', 'test'):data(false)
 
@@ -340,6 +379,15 @@ function test_unset_data()
   assert_match('Content%-Disposition:.-name="test"', info)
 end
 
+function test_unset_data_by_null()
+  mime:addpart():data('hello', 'test/html', 'test'):data(null)
+
+  local info = assert_string(dump_mime(mime))
+  assert_not_match('\r\n\r\nhello', info)
+  assert_match('Content%-Type:%s+test/html', info)
+  assert_match('Content%-Disposition:.-name="test"', info)
+end
+
 function test_unset_data_type_1()
   local part = mime:addpart():data('hello', 'test/html', 'test', {
     'X-Custom-Header: hello'
@@ -352,6 +400,18 @@ function test_unset_data_type_1()
   assert_match('X%-Custom%-Header:%s*hello', info)
 end
 
+function test_unset_data_type_1_by_null()
+  local part = mime:addpart():data('hello', 'test/html', 'test', {
+    'X-Custom-Header: hello'
+  }):data('hello', null)
+
+  local info = assert_string(dump_mime(mime))
+  assert_match('\r\n\r\nhello', info)
+  assert_not_match('Content%-Type:%s+test/html', info)
+  assert_match('Content%-Disposition:.-name="test"', info)
+  assert_match('X%-Custom%-Header:%s*hello', info)
+end
+
 function test_unset_data_type_2()
   local part = mime:addpart():data('hello', 'test/html', 'test', {
     'X-Custom-Header: hello'
@@ -376,6 +436,18 @@ function test_unset_data_name_1()
   assert_match('X%-Custom%-Header:%s*hello', info)
 end
 
+function test_unset_data_name_1_by_null()
+  local part = mime:addpart():data('hello', 'test/html', 'test', {
+    'X-Custom-Header: hello'
+  }):data('hello', nil, null)
+
+  local info = assert_string(dump_mime(mime))
+  assert_match('\r\n\r\nhello', info)
+  assert_match('Content%-Type:%s+test/html', info)
+  assert_not_match('Content%-Disposition:.-name="test"', info)
+  assert_match('X%-Custom%-Header:%s*hello', info)
+end
+
 function test_unset_data_name_2()
   local part = mime:addpart():data('hello', 'test/html', 'test', {
     'X-Custom-Header: hello'
@@ -400,6 +472,18 @@ function test_unset_data_header()
   assert_not_match('X%-Custom%-Header:%s*hello', info)
 end
 
+function test_unset_data_header_by_null()
+  local part = mime:addpart():data('hello', 'test/html', 'test', {
+    'X-Custom-Header: hello'
+  }):data('hello', nil, nil, nil, null)
+
+  local info = assert_string(dump_mime(mime))
+  assert_match('\r\n\r\nhello', info)
+  assert_match('Content%-Type:%s+test/html', info)
+  assert_match('Content%-Disposition:.-name="test"', info)
+  assert_not_match('X%-Custom%-Header:%s*hello', info)
+end
+
 function test_unset_data_filename_1()
   local part = mime:addpart():data('hello', 'test/html', 'test', 'test.html', {
     'X-Custom-Header: hello'
@@ -409,7 +493,20 @@ function test_unset_data_filename_1()
   assert_match('\r\n\r\nhello', info)
   assert_match('Content%-Type:%s+test/html', info)
   assert_match('Content%-Disposition:.-%sname="test"', info)
-  assert_not_match('Content%-Disposition:.-%sname="test%.html"', info)
+  assert_not_match('Content%-Disposition:.-%sfilename="test%.html"', info)
+  assert_match('X%-Custom%-Header:%s*hello', info)
+end
+
+function test_unset_data_filename_1_by_null()
+  local part = mime:addpart():data('hello', 'test/html', 'test', 'test.html', {
+    'X-Custom-Header: hello'
+  }):data('hello', nil, nil, null)
+
+  local info = assert_string(dump_mime(mime))
+  assert_match('\r\n\r\nhello', info)
+  assert_match('Content%-Type:%s+test/html', info)
+  assert_match('Content%-Disposition:.-%sname="test"', info)
+  assert_not_match('Content%-Disposition:.-%sfilename="test%.html"', info)
   assert_match('X%-Custom%-Header:%s*hello', info)
 end