Sometimes I forget to empty the waste container on my smart Vac/mop and then it well create the worse smell. What I’ll do is pour baking soda all over the container and then flush it with vinegar. As long as I get the entire container once it dries the funk is gone. I’m unsure if your wireless stick can be flushed as I’ve never worked with it so make sure this won’t cause an issue before trying this method. A safer approach would be to try and simmer the vinegar in a pan with the filter and motor very close to the pan (make sure motor is exposed). This may kill everything that’s causing the smell.