Needed to spray some herbicide this weekend and the sprayer was full of crude. Found a safe place to dump it and rinsed it out. Now to refill it. I've got a 15 gallon supply of the herbicide that tends to collect floaties and other things that won't go through the nozzle. Needed a strainer and was out of cheese cloth and paper paint strainers. I spotted and old paper dust mask and it worked fine. It even fit (and stayed) in the fill nozzle of the sprayer. YMMV!