The recycling of fridges results in the production of a mixed plastic product containing high impact polystyrene (HIPS) and acrylonitrile butadiene styrene (ABS). These plastics are difficult to separate because they have similar physical properties, such as density. Froth flotation using selective wetting agents is one possible separation technique. The use of acetic acid, methanol and quebracho as selective wetting agents have been investigated. All are shown to be potentially selective given idealised flotation conditions, with similarly sized particles. The use of quebracho at pH I I gave the most promising results producing selectivity over a wide particle size range. (C) 2004 Elsevier Ltd. All rights reserved.