Just look at the pump and follow the flow up water from the tank to the inlet, and the outlet to the boom.  And remove any water traps.  Gravity flows downhill so work your way from the tank down through the pump and booms.

For example, when I clean out something sensitive, I 

(optionally) flush, then

spray out the tank, then turn off the pump, open the valve for filling the tank (bc it is a low point) and let it drain, then open the sparge valve and let it drain, and open/wash the main screen at the outlet of the pump (low point) to let it drain, 

then close it all back and fill with 100 gal of water and appropriate cleaner to chemicals in tank (whether a soap like glyphosate or Erase or something to chemically deactivate the target chemical with appropriate waiting time) and rinse down tank, flush it out the booms, and repeat the clean out above,

Then dump and wash the boom strainers/screen,

Then blow out the boom ends


Then when I switch to a sensitive crop I flush the boom at the field edge.

Overkill, sure, but I don’t have any crop damage.


If you are using hot loads your hot load tank is now much dirtier than your sprayer.