So, these do what they need to and they don't have any scent which is pretty important for a mask that goes right over your nose. But there are other brands (i.e., MedPro Defense) that do the same thing and they are biodegradable and they cost less than half as much. For anything I use every day and throw out, not having to toss them into a landfill is a huge consideration, as is the monthly cost. And the other brand lists their ingredients while Purdoux just says "natural" but provides no disclosure on what is in them. These work, but I'm switching brands.