According to the requirements of Good Manufacturing Practice, the pharmaceutical industry is obligated to perform cleaning validation to ensure the quality and safety of products. Cleaning validation is documented evidence that the cleaning process appropriately and consistently removes all residues of previous product, by-product, microorganisms and cleaning agents. Its purpose is the timely identification and correction of potential issues. To evaluate the cleaning process, it is necessary to determine the acceptance criteria - Acceptable Residue Level (ARL). The aim of this thesis is divided into two parts. Firstly, the analysis and experimental examination of the problem of cleaning efficiency of products on a specific mixer. The cleaning conditions were stimulated in the laboratory, analyzing different washing methods. The aim is to determine which of the six possible products leaves residues after cleaning and which of the tested methods ensures the best level of cleanliness. The experiment included weighing the plates, applying the product, drying and applying washing methods – purified water, COSA CIP92 and CIP72 detergent solution and ClearKlens Mega detergent. The second aim is focused on validating the effectiveness of the existing cleaning method to ensure that there are no residues of the active ingredient and detergent on the equipment. The HPLC and TOC methods were used to confirm the absence of residues. The experimental results indicate that the applied detergents are more effective than purified water. The biggest problems were caused by product 2 and product 4, which required specific approaches. In the end, a cold 1%-CIP92 detergent solution was effective for product 4, while the issue with product 4 remains unresolved and requires further analysis. The cleaning validation confirmed the effectiveness of the existing method. All samples were found to be within acceptable limits.