diff --git a/src/smtp_server.erl b/src/smtp_server.erl
index 8641162..6636d41 100644
--- a/src/smtp_server.erl
+++ b/src/smtp_server.erl
@@ -107,16 +107,13 @@ handle_MAIL(From, State) ->
 
 %% @doc Handle an extension to the MAIL verb. Return either `{ok, State}' or `error' to reject
 %% the option.
--spec handle_MAIL_extension(Extension :: binary(), State :: #state{}) -> {'ok', #state{}} | 'error'.
 handle_MAIL_extension(Extension, _State) ->
 	io:format("Unknown MAIL FROM extension ~s~n", [Extension]),
 	error.
 
--spec handle_RCPT(To :: binary(), State :: #state{}) -> {'ok', #state{}} | {'error', string(), #state{}}.
 handle_RCPT(_To, State) ->
 	{ok, State}.
 
--spec handle_RCPT_extension(Extension :: binary(), State :: #state{}) -> {'ok', #state{}} | 'error'.
 handle_RCPT_extension(Extension, _State) ->
 	io:format("Unknown RCPT TO extension ~s~n", [Extension]),
 	error.
@@ -193,7 +190,6 @@ handle_RSET(State) ->
 	% reset any relevant internal state
 	State.
 
--spec handle_VRFY(Address :: binary(), State :: #state{}) -> {'ok', string(), #state{}} | {'error', string(), #state{}}.
 handle_VRFY(_Address, State) ->
 	{error, "252 VRFY disabled by policy, just send some mail", State}.
 
@@ -228,10 +224,6 @@ handle_AUTH_user(Type, Password, _UserPassword, _State) ->
 	io:format("handle_AUTH error ~w ~w ~n", [Type, Password]),
 	error.
 
--spec handle_info(Info :: term(), State :: term()) ->
-    {noreply, NewState :: term()} |
-    {noreply, NewState :: term(), timeout() | hibernate} |
-    {stop, Reason :: term(), NewState :: term()}.
 handle_info(_Info, State) ->
 	{noreply, State}.