Processors were looking to improve recyclability and boost the availability of recycled High-Density Polythene (rHDPE) by a switch away from coloured milk bottle tops.
Aldi was trialling scrapping green bottle tops on its British Semi Skimmed Standard Milk products in favour of clear caps.
Working in partnership with milk supplier Muller, the trial will be introduced later this month across stores in Cheshire, Manchester and Liverpool.
If successful and rolled out to all Muller-supplied stores, an additional 60 tonnes per year of rHDPE could be recycled into food-grade packaging and bottle caps reused to create new milk bottles.
Liam McNamara, joint chief executive at Muller Milk and Ingredients, said: "In an industry that needs access to more rHDPE, we are working hard to innovate and lead on issues that are not only important for customers but for consumers too."
He added the milk bottles already contained up to 40 per cent recycled material but with access to more they could increase this.
Back in April, the processor partnered with Waitrose to trial a similar move in its 331 stores, which has now been rolled-out.
It comes as Freshways sent a letter to its customers and farmers on August 15 detailing its decision to remove the colour from all its milk and cream caps to improve recyclability and reduce the food industry鈥檚 dependence on virgin plastic from the end of August.
Bill O鈥橲ullivan, Freshways director of national retail and wholesale said: "This change will mean that more than 300 tonnes of food-grade plastic will be available for reuse to the food sector each year."
