It is a perennial problem. I've tried simply straining the liquid but it has never gone through a regular sprayer. You might try straining through a coffee filter, though.
I've been wanting to try a new, clean hand garden sprayer. One of those might work since they should be able to be used with water-powder emulsions, no? I wonder what type of sprayer that BBQ teams use? A mop? Squirt bottles, in spite of the runoff?
Are there any competition teams out there who could make some suggestions?
Rita