I have a 5 gallon backpack sprayer that I have used malathion and liquid seven spray in. I was wondering if there is something that would clean the sprayer well enough to use it for worm tea or fish emulsion. I didnt want the contents of the residual spay in the container to negate the microbes of the worm tea or enzymes of the liquid fish. Any suggestions or should i use a different spayer. Is anyone else noticing a large ammount of caterpillars. I have a copius ammount of them. Normally I wouldnt spray my blueberries bushes. However, I have some newly planted one year old bushes with limited amounts of growth on them. I think a caterpillar could kill some of them by defoliating them. Suggestions would help? thanks