This hack* is to do with identifying which of the 1-in-5 bars is a winning wrapper (or not) for the Cadbury "Score a Freebie Bars Promotion" that expires at the end of this month. Get in quick before all the promo bars are replaced with new stock!
Update: This deal/hack/promo has been just a tad popular (gee, thanks everyone!) and it may well be that all of the winning bars have already been taken at your local store. It has been reported in the comments that some of the larger stores/chains have either stopped redeeming bars or taken promo bars off the shelves entirely so you might have more luck at smaller chains or service stations.
This works for pretty much the whole range of medium bars, in approximate order of easiest-to-identify-to-hardest:
40g TimeOut
52g Cherry Ripe
50g Crunchie
46g Picnic
39g Twirl**
60g Boost**
ONLY the winning wrappers have a barcode printed on them on the inside of the wrapper. This barcode can be identified on the outside of the wrapper by looking for VERY slight indentations as in the attached scan (a thin red square has been drawn around where you should be looking). Reflect the bright store lights off the wrapper and if you are lucky the indentations will be visible in approximately the same place.
You have to buy your first bar (which are on special/clearance at the moment at most major supermarkets), but after that in theory you can redeem the winning wrapper for another winner carefully selected by yourself, ad infinitum.
As far as I can tell, posting this does not invalidate or contravene the terms and conditions of the promotion:
http://www.cadbury.com.au/Competition/Score-a-Freebie-Bars-P…
Enjoy!
*There was only a "Freebie" tick-box when submitting the deal, so I ticked that. If there was a "Life Hack" or "Other" tick-box I would have ticked it when creating the deal, my apologies to all the Captain Literals out there who have said this is not technically a bargain, they are probably right ;)
**Twirl and Boost are harder to identify unless you know exactly what to look for and have a really good eye.
Can you see the indentations in the scan/link attached to this thread? They are within the thin red box I added with my l33t mspaint skillz heh (zoom in with your browser if it helps, hold down control and scroll in with mousewheel I think should zoom in)
Angle the wrapper so your eyes aren't distracted by any colour of the wrapper itself, so you can only see the shine/reflection of your light source. The imperfect reflections in the light are what you are looking for, don't stretch or crinkle the wrapper too much or it will be harder to see… Good luck!!!