Beware of aluminum wire safety hazards! Aluminum wire was used pre-1970's for home wiring, but it was found to be a safety hazard. Since aluminum wire was found to be almost as conductive as copper wire, only cheaper, for a few years, home wiring was done in aluminum wire.
You see, aluminum is a much lighter and softer material that expands and contracts due to the amount of heat generated from the current passing through it. As a circuit's load is increased, so is the temperature of the wire. This often times softens the wire and loosens the electrical connection points. When this happens, a loose connection acts like a resistance or increased load on the circuit. This generates more heat and can cause electrical fires!
So if you have aluminum wiring in your home, you may be asking yourself if it is safe. If you are unsure if you have aluminum wiring or want to have it checked for safety purposes, I recommend calling a licensed electrician to examine your homes wiring.
If you'd want to do it yourself, a good rule of thumb is to turn of the breakers at the circuit breaker panel and tighten each connection point there first. This includes the breaker connections, along with the neutral and ground connections. Then, go to every junction box to see if the splices are all still tight. Next, check the connections on switches and outlets to be sure those are tight.
Just because you do have aluminum wiring in your home, doesn't mean that it isn't functional. As long as the connections are secure and checked periodically, your home should be fine.