Method for verifying the result of a cleaning process to remove simulated chemical and/or microbiological contaminants previously applied to a test area, comprising the following steps: a) providing a coating device having a filled cartridge containing a test liquid for simulation of chemical and/or microbiological contaminants, wherein the test liquid contains a defined type and concentration of chemically and/or microbiologically contaminating substances; b) selecting a defined test area and applying a defined quantity of test liquid to the test area by means of the coating device; c) performing a standardized cleaning process on the test area provided with the test liquid; and d) verifying and logging the result of the cleaning process performed, characterized by : e) an inkjet printer as the coating device; and f) the following verification steps: fa) wiping over the previously contaminated and subsequently cleaned surface of the test area in a first form with a neutral cleaning element, and removing the traces picked up from the surface of the test area by the cleaning element on wiping, using a solvent; or fb) treating the previously contaminated and subsequently cleaned surface of the test area in a second form in a vessel containing a solvent; and fc) testing the traces-loaded solvent in an analyser; wherein fd) the analysis result indicates whether the cleaning process was successful or whether residues of the contaminating test liquid above the permissible level remained on the test area, meaning that the cleaning process must be repeated or be intensified from the beginning in order to achieve an acceptable level of cleanliness. a) providing a coating device having a filled cartridge containing a test liquid for simulation of chemical and/or microbiological contaminants, wherein the test liquid contains a defined type and concentration of chemically and/or microbiologically contaminating substances; b) selecting a defined test area and applying a defined quantity of test liquid to the test area by means of the coating device; c) performing a standardized cleaning process on the test area provided with the test liquid; and d) verifying and logging the result of the cleaning process performed, characterized by : e) an inkjet printer as the coating device; and f) the following verification steps: fa) wiping over the previously contaminated and subsequently cleaned surface of the test area in a first form with a neutral cleaning element, and removing the traces picked up from the surface of the test area by the cleaning element on wiping, using a solvent; or fb) treating the previously contaminated and subsequently cleaned surface of the test area in a second form in a vessel containing a solvent; and fc) testing the traces-loaded solvent in an analyser; wherein fd) the analysis result indicates whether the cleaning process was successful or whether residues of the contaminating test liquid above the permissible level remained on the test area, meaning that the cleaning process must be repeated or be intensified from the beginning in order to achieve an acceptable level of cleanliness. fa) wiping over the previously contaminated and subsequently cleaned surface of the test area in a first form with a neutral cleaning element, and removing the traces picked up from the surface of the test area by the cleaning element on wiping, using a solvent; or fb) treating the previously contaminated and subsequently cleaned surface of the test area in a second form in a vessel containing a solvent; and fc) testing the traces-loaded solvent in an analyser; wherein fd) the analysis result indicates whether the cleaning process was successful or whether residues of the contaminating test liquid above the permissible level remained on the test area, meaning that the cleaning process must be repeated or be intensified from the beginning in order to achieve an acceptable level of cleanliness. <EOS>