There’s a good reason why large shop-vacs come with reusable or replaceable filtering systems. They’ll be clogged all the time from the dust of a job site or home improvement effort. That’s why so many are made to be washed out and staying on top of that is important. If your allergies or those of others in your household are severe, shift your messy projects outdoors or to a larger open area like a garage. Consider other methods of keeping the dust out of your lungs, like wearing individual breathing masks rated for smaller particulate matter. Buy a vacuum with a reusable dust filter that can be cleaned after each use to avoid ongoing expenses. Remember that liquids can carry allergens and toxic substances too. You’ll want to take precautions when working around solvents or chemicals, even outdoors. Some are best sopped up, not sucked up, so read your product labels for the manufacturer’s recommendations.