Abstract: The invention relates to a cleanser concentrate having the following composition: 0.5-8.0% by weight of at least one C.sub.5 -C.sub.12 -alkyl sulphate salt, 4.0-15.0% by weight of at least one formulation aid, 4.0-10% by weight of at least one alkanolamine, and at least one commercially conventional proteolytic enzyme in an amount of 0.005-0.1 Anson and, if appropriate, conventional acids or bases for pH adjustment, conventional complexing agents and conventional preservatives, remainder, to 100% by weight, water. A process for cleaning surgical instruments has the following steps: applying a 0.5-100% strength aqueous solution of a cleanser concentrate according to one of claims 1-6 which has a pH of 8-9, allowing the solution to act at a temperature of room temperature to 55.degree. C. for a period of 2 s-20 min, rinsing, thermal disinfection, if appropriate.