High pressure lean amine pump performance dropped within a span of about 1 month due to internal fouling. Fouling was caused by accumulation of iron sulphide. To address the fouling, pump would have been to taken out of service for a full overhaul, resulting in extended downtime and high cost of repair. Offline chemical wash with 1% EDTA solution pursued as an alternative to the pump overhaul. Prior to commencing with the chemical wash, material compatibility of pumps/mechanical seals wetted parts, and process fluid flow path were considered as part of the technical evaluation. During chemical wash, samples were regularly collected at the circulation outlet to check for appearance in order to determine progress of the chemical wash in removing the foulants. Pump performance recovered upon completion of the chemical wash.