Do a search on
http://www.yellowpages.com.au for scrap metal merchants, call them up tell them the weight of your aluminum and ask if they'd buy scrap aluminum.
Some scrap guys don't pay, they just come and take annoying large metal things off your property for free, and melt it down to make money out of it later. I've had things removed like this, its handy if you just need something large and heavy gone. But metal is expensive and if you have the time and the tools its worth it. Some scrap metal merchants / recyclers you can take your stuff there and you get $$.
For example, aluminum is expensive, you can strip a house under construction of its aluminum door and window frames in 5 minutes with a strudy flat head screw driver. This will get you I think around $ 100 - $ 150 at a smelter. Not that I recommend this practice nor do I partake.
A can fetches you 5 c in S.A. because to those guys who melt it down its probably maybe almost worth that. Nangs are much heavier, and contain a lot more aluminum. Cans are probably a higher grade aluminum than nangs, but both are made for consumption, so I don't know with nangs. They could be worth a small amount of cents each?
Fridges can also be redeemed for cash. See one lying on the side of the road? Want some money? Remove all but the different metals, take it to someone who melts the shit down and you got at least $50 probably more. The older the better.
If you've got a truck full of these empty nangs, you may be able to retire early kwiksand.
Otherwise a scrap metal guy will come and take them away I'm sure.