The above alcohol may also function as aco-emulsifying agent.Furthermore the micro-emulsion can comprise a compound according to formula I: ##STR2##wherein X is OH, O.sup.- or a polymer backbone.The counter ion can be, depending on the pH, H or a metal such as an alkali or alkaline earth metal or a transition metal, e.g. chromium.Suitable examples of the compound according to formula (I) are polyv