Probably more than half of Eastern Europe is wired with aluminium, and some war-time stuff still hangs around in Western Europe. Those houses don't burn all the time, but some do. Apparently the biggest problem with the alloys commonly used for home wiring is mechanical, namely flowing under pressure. I talked to an expert in chemistry and he said that the oxide layer really isn't an issue you need to worry about because you can't prevent it, if you remove it mechanically or chemically it will return before you have any chance to terminate the wire. He also said that corrosion of copper-aluminium connections is only possible if water is present, therefore it is recommended to use vaseline on any exposed Al wire.
Last weekend I did a thorough check of some Czech wiring and those parts wired with copper had far more loose screws than those wired with aluminium. Might have something to do with the actual load though as the Al was limited to lighting circuits. On the other hand, the 6 mm2 Al main feed was rock solid too. So I guess you can't generalise.
On the other hand, Al definitely breaks more easily when nicked, so you have to be extra careful when stripping Al.
