Something I use everyday that can be considered as waste is my plastic cup. Yes, I may use the cup a few more times after the first use but I eventually throw it away. It’s considered waste because once I feel as if its use is no longer needed then I no longer have to keep it. I would rinse the cup and reuse it for the day sometimes but I would not keep it for multiple days.
Mary Douglas implies that “washing, scrubbing, isolating, and disinfecting has only a superficial resemblance with ritual purification”. We focus a lot on hygiene and whether or not something is clean or dirty. For instance if the worshipers didn’t shower, they would be wasting time trying to pray because they were impure. Anyone who would be in contact with them, clean or dirty will become impure. In my cup scenario, since it’s been left on the counter for hours after being cleaned, it can become dirty because it’s an open cup and could easily be contaminated, therefore it’s a waste.