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The modern polymer material which previously applied on conservation of cultural artifacts about 30~40 years ago really prolong the life of the heritages,especially for those fragileheritage.However,those polymer resins always degrade with time due to cross-linking reactions and chainscissions.When polymers are used on the surface of outdoor cultural heritage like wall paintings in situ,surface hydrophobicity will strongly increase and prevent from natural "breathing" process.Mechanical stress will generate beneath the painted layer due to salt crystallization.This leads to complete disruption of the painted layer after years.Normally conservators choose organic solvents to remove the conservation resins used in previous treatment.However,the cross-linking of resins results in the loss of solubility,which makes the cleaning irreversible.Imitation experiments were carried out in order to choose suitable micelle solutions to remove degraded Sanjia acrylic resins(MMA/BMA/MA,unknown proportion)on painted mortar panel,because this polymer was widely used in conservation field of China in last 40 year.The oil-in-water microemusions is an amphiphile-based system.Compared to organic solvents,the system is low volatility and not combustible.The special characteristics are high efficiency of cleaning treatmentandsafetyfor both of conservator and cultural heritage.In this paper,the solubility parameter of those unknown agingresines which was applied on wall paintings 40 years ago is determined by turbidity titration method.Three different O/W microemulsions and micelle solutions have been studied to dissolve acrylic polymer.Optical Microscope,contact angle measurements,FTIR,and SEM/EDX results showed that the O/W microemulsion were very effective in removing acrylic or vinyl polymeric resins from wall paintings in situ.The aging acrylic polymers produced serious degradation like gloss,yellowing and flake on the painting layers of the wall paintings in tomb of the northeast of China.The acrylic polymerhave been successfully removed by this kind of O/W microemulsions with the pressure technique.