| abstract |
A method of reducing paraffin deposits on a paraffin contaminated surface. The surface is contacted with a sulphur trioxide containing liquid to react with the paraffin, and convert at least a portion of it to a water-dispersible material. The surface is also contacted with a surfactant containing or providing liquid, so as to reduce the amount of organic precipitate formed by the action of the sulphur trioxide on the paraffin. Additionally the surface is usefully rinsed with an aqueous liquid, preferably an aqueous alkaline liquid, following it being contacted with the sulphur trioxide. The surface may be contacted with the surfactant containing liquid, either prior to, or subsequent to, contacting it with the sulphur trioxide containing fluid. |