Coumaphos is an organophosphorous acaricide which is used for control of cattle ticks in vats. Methods fo stabilization of coumaphos i.e. increased shelf life for the use of coumaphos suspension in the vats by maintaining pH has been given. Huge quantity of coumaphos waste solution is generated because of decrease in efficacy after prolonged use with treatment of large number of cattle. Procedures for safe disposal of coumaphos in soil by dealkylation and use of UV and solar radiation are described.