This study aims to propose evaluation methods of chemical washing performance and estimate the washing capability by flowing detergent/water solution for application to home appliances such as dishwashers. Standard pollutant is stearic acid. A numerical study is also tried using a SIMPLER code. Preliminary experiments are performed by varying the concentration and temperature of the solution. From the pre-experiments, 10 minute pre-curing time is found to be necessary to remove the stearic acid. Stoichiometric ratio and detergent consumption coefficient of reaction between the detergent and stearic are estimated following a proposed method. Washing experiments of pollutant to compare with the numerical results are performed. The relative errors between the experimental and the numerical results with pre-curing time included are less than 7%. In conclusion, important mechanisms of chemical washing are revealed and methods of predicting washing performance are well established.