A powdered detergent formulated for the refurbishment of drinking glasses especially to remove rinse aid film. Also in the pre-treatment of new drinking glasses to remove all traces of chemicals used in glass manufacture especially the mould release agents. In both cases the head retention and lacing characteristics of beers will be maximised since both rinse aid film and mould release agents rapidly collapse the beer head. May be used as an aid to the normal maintenance cleaning of cabinet and rotary brush type glasswashing machines where the detergent action of the product will benefit the machine interior. Recommended for use in public houses by all the major brewery companies.