Hot washing is a cleaning step in plastic recycling in which flakes are washed in heated water, typically between 60 and 90 degrees Celsius, with caustic soda and detergents. It removes contaminants that cold water leaves behind.
Heat and chemistry dissolve label glue, oils, grease, food residue and some inks, and reduce odour in the final granules. Hot washing is standard for PET bottle flakes and is increasingly used for polyethylene and polypropylene packaging where a clean, low-odour grade is required. It is followed by rinsing, density separation and drying. The process uses energy and water, so modern washing lines recover heat and treat and reuse the wash water. At Lucro’s washing centres, 95% of the water used is recycled.
