The term 'wombling' conjures up images of Uncle Bulgaria and the gang on Wimbledon Common. But it's also the name of a new moneysaving craze, helping shoppers to save money at the supermarket.
Wombling is where you collect up old supermarket receipts from in and around a shop – generally picked out of the bin or found in old trolleys – and collecting the points left on them.
But before you start scanning the floor for discarded vouchers, the rules around how to womble are pretty grey and the supermarkets are not on board.
How Wombling can save you money
Several supermarkets, including Tesco and Asda, offer price guarantees. So if you shop at a rival supermarket and it's cheaper, you're able to claim the difference back.
To do this you have to take the receipt into the shop and either scan it at the checkout or enter the code from the receipt online to get a voucher for the difference.
At Tesco and Asda for example, if a comparable food shop at Sainsbury's or Morrisons is cheaper you'll be given a voucher for the difference, up to a maximum of £10.
What the womblers do is collect other people's discarded receipts, and in essence take the points - and the cash - for themselves. By doing this you can make quite a bit of money.
But there's quite a big catch.
There are quite a few people wombling in the UK and saving money on their shopping. But the supermarkets aren't keen on it.
Many state in their terms and conditions that vouchers are only available for the person who has received them. Therefore if you're caught using points which you've not received on your own shop, they will be deducted from your account.
Tesco, for example, says the terms and conditions of its price promise include a fair use policy, and it considers using other customers' lost or unused vouchers to be in breach of this policy.
Nectar follows a similar line. In its card rules customers agree that points are only provided against their own transactions.
It says: "Points can only be earned, held, transferred or redeemed as set out in these rules. Any other use, award, sale, exchange or transfer of points, or attempt to do so, is a serious breach of these rules.
"Any points not earned and held in accordance with these rules will be invalid, cannot be redeemed for rewards and will be deducted from the applicable account."
However, in reality a supermarket won't ask you to confirm your identity when you enter a code online to redeem a discount. This means many people are still risking wombling to get their hands on extra cash, even though it's not technically allowed.