Maintaining & keeping your trailer clean is as important as owning the trailer itself, this is your investment and it will enhance the trailers lifetime. It will give you a higher resale value (ROI) when you go to sell or trade in. It is fine to use a power washer on your trailer provided a gentle detergent is used. You must not direct hose at electrics/lighting. It is important to remember that hard abrasive chemicals should not be used as these can damage the protective coating already on your trailer. Use of a quality vehicle wash/wax solution and soft brush scrub is preferable.When using your trailer with animals, chemicals or acids & alkali, always, always rinse off at minimum within the hour. Great tools make working life easier, always clean down your tools and maintain them. Annually & monthly, you will have a safer, efficient and time saving tool with no rust, no stiff joints and your buiness looks good onsite. Use grease and proprietary lubricant like WD40 or Lanox or Inox on moving parts.