Residue Removal and Cleaning Methods

As identified previously, cleaning relies upon the solubilization, chemical reaction and physical action for removal of residuals.

Some of the methods for achieving residue removal in these categories include: dissolving, suspending, emulsifying, sequestering, wetting, saponifying, and scraping, brushing and scrubbing.

The effectiveness of a cleaning agent when in contact with the residue that is to be removed may be dependent upon such parameters as the cleaning agent concentration, exposure time, pressure, temperature or pH.

Often the interactions of the cleaning agent and the process residue are not enough to result in
effective cleaning. In these instances, additional techniques such as agitation, direct impingement,
and disruption by ultrasonic vibration have proven useful to facilitate residue removal.

The determination of the cleaning cycle will depend upon equipment design criteria, surface
characteristics, geometry and composition.

The equipment design criteria will affect the amount of residual remaining on equipment surfaces and the ease with which such residuals are removed.

In most types of cleaning, some disassembly of the equipment may be required. Disassembly is critical in providing access to previously inaccessible areas of the equipment as well as providing the opportunity to visually examine the internal surfaces to verify that they have been effectively cleaned by the cleaning process.

It is important to include disassembly directions in the cleaning SOP and training activities to ensure reproducibility of cleaning.