From what a fireman told me, ALL fire extinguishers are one-use.

If the head is metal, it's probably refillable, and it should be refilled by a professional after any discharge (the fire dept can recommend one). If any part of it is rusty or corroded, they probably won't refill it.

The ones with the plastic heads aren't refillable; if the tank is aluminum, take it to a recycling facility. If it's made from anything else, send it to the dump.

Sue