Cleaning clutter is generally not something you can outsource directly.  You generally at least need to take the first pass of sorting through things before deciding what to keep and what to throw away.  There are the traditional fall or spring cleanings, but this really only scratches at the surface of what cleaning out clutter is really all about.

It is imperative that the workplace stays neat, organized and clear of clutter. Clutter in the work-space may kill your creativity and equally as important, your relationship with your clients. Doing away with unnecessary clutter will clear your mind and elevate your productivity. You need a less distracting place to work overall.

A Clean Space

Having a clean space to work will prove to be impressionable. Most people want to see and know that you take your work seriously.
Organization and tidiness will allow you and your clients to be more comfortable in the space.
Clutter may be a sign of procrastination as well. Are you one who sees a task as physically or mentally overwhelming and put it off for another time? Keep you workplace neat and free of clutter in order to kick the bad habit and improve your mental health.

It is important to keep your stress level as low as possible, especially at work. Being able to see clearly and immediately locate documents or other items will keep stress levels at a minimum. Being clutter free will also serve as an aid to any deadline you may be faced with. Keeping your space in order is one of the biggest pros to meeting your deadlines.

https://www.theladders.com/career-advice/8-benefits-of-decluttering-your-workspace

http://info.totalwellnesshealth.com/blog/organize-your-workspace-for-improved-mental-health

https://www.inc.com/indigo-triplett/creating-a-clutter-free-mind-by-creating-a-clutter-free-space.html