A small cut from a rusty iron is not very risky and can be cleaned with saline and then disinfected with iodophor. If the wound is deeper and more contaminated, then it needs to be cleaned with saline and hydrogen peroxide. Some of the decayed tissue will be debrided and the wound will also need to be injected locally with tetanus antitoxin. Keep the wound clean and clear to avoid secondary bacterial infection. If the wound is superficial, there is no need to inject tetanus antitoxin, and sterilizing it with iodophor will do.