Critical infrastructure cyber-physical systems heavily depend on accurate data in order to facilitate intelligent control and improve performance. Corruption of data in these systems is unavoidable, resulting from both intentional and unintentional means. The consequence of making control decisions based on erroneous or corrupted data can be severe including financial loss, injury, or death. This makes employing a mechanism to detect and mitigate corrupted data crucial. Many techniques have been developed to detect and mitigate corrupted data. However, these techniques vary greatly in their capability to detect certain anomalies and required computing resources. This chapter presents a survey of data cleansing techniques and their applicability to various control levels in a critical infrastructure cyber-physical systems.