void ClearHudMessage(int id)
ClearHudMessageBold(int id)

It is often needed to clear a HudMessage. These functions are a shorthand for HudMessage(s:“”; HUDMSG_PLAIN, id, 0, 0.0, 0.0, 0.0, 0.0);, so you don't have to think about all the zero arguments to HudMessage.