Abstract: A method of purifying a mixture, said mixture comprising an oil Product, at least one additive and water, wherein: said oil Product is a liquid fuel oil composition or lubricating oil composition, at least part of the water is in the form of a dispersion of water in said Product, and said additive is a cyclic compound comprising m units of the formula (Ia) and n units of the formula (Ib) joined together to form a ring, wherein each y and Y2 is a divalent bridging group which may be the same or different in each unit; R0 is H or (C1-C6) alkyl or is a metal cation, R5 is H or (C1-C60) alkyl; J is 1 or 2; R3 is hydrogen, a hydrocarbyl or a hetero-substituted hydrocarbyl group; either R1 is hydroxyl and R2 and R4 are independently either hydrogen, hydrocarbyl or heterosubstituted hydrocarbyl, or R2 or R4 are hydroxyl and R1 is either hydrogen, hydrocarbyl or hetero-substituted hydrocarbyl; and m+n is from 4 to 20, m is from 1 to 8 and n is at least 3; said method comprising: providing said mixture, coalescin