All summer you have diligently maintained, calibrated and cleaned out your sprayer.
Good winterizing and storage of your sprayer can ensure that next year when you pull it out of your shop it will function properly.
Here are a few tips that you can use to make winterizing easy.
Rinse : Prior to storing a sprayer for the winter it needs to be thoroughly rinsed of all pesticide residues. It is better to rinse the sprayer several times with a small amount of clean water than to fill it up only once.
Dispose of the rinsate in a field that has proper setbacks from all water sources. Do not allow the rinsate to accumulate into puddles. It is preferable to rinse the sprayer on an impervious surface where the rinsate can be collected and taken to a Clean Sweep site.
At this time make sure all water is drained out of the sprayer so no damage is caused by water freezing.
Once the inside of the tank is cleaned out do not forget about the outside of the sprayer. The outside should be rinsed with clean water and if at all possible on an impervious surface and the rinsate collected.
Always remember to read the label of the pesticide used and use appropriate personal protective equipment when cleaning.
Clean : Once you have the tank properly rinsed the next step is to decontaminate it. You can purchase commercial cleaning agents or you can clean your system with some common household products. For a chart of the product and amount that you should use consult “Maintenance, Cleaning and Storage of Ground Sprayers”  Montana State University Extension Bulletin number MT198917AG.
Run through entire system
Remember to run the cleaning solution through the entire system including agitation and return lines. Rinse clean water through the system after it has been thoroughly cleaned opening up the nozzles and running the water until only clean water is coming out.
Maintance: Now that your sprayer is rinsed and cleaned carefully inspect the system making note of any maintenance concerns and repairing them. Look at nozzles, screens, hoses, valves, pumps, boom, as well as the tank.
Now is a good time to check for tank integrity. See How to check poly tank condition using three different methods.  Now is also the time to make any modifications that you need to make. Please remember that even though the system has been cleaned you still need to be cautious and wear all labeled personal protective equipment.
Storage: The final step is to properly store the system. Any removable parts should be removed to ensure there is no damage during storage. For example nozzles, filters, tips, check valves, screens, pressure gauges. If at all possible store these in an area that will not freeze.
Clean filters with soapy water before storage.
The last step is to circulate antifreeze throughout the system including the boom’s hoses. Cap the boom nozzles, one or two nozzles may need to be left open to ensure total circulation, and remember to cap them when the system is filled, to make sure antifreeze is in the entire system.
Your system is now ready for storage. If you have foam markers and flowmeters don’t forget to clean these also. To clean them follow the manufacturers suggestions.
For more information please consult “Maintenance, Cleaning and Storage of Ground Sprayers”  Montana State University Extension Bulletin number MT198917AG.