Mouse poop and cleaning

So frustrated. We had mice a couple months ago and got rid of them successfully. I have cleaned the floors more than a hand full of times and keep finding random little poops. I know it’s old because we haven’t had any indication of mice. My baby was playing near her cubby’s and of course there was a piece. She’s one and didn’t notice it but I did and my anxiety triggered. My husband won’t get a professional cleaning and leaves it up to me and I’m trying my hardest I swear I’ve gotten everything and then a random piece will show up. Has anyone else dealt with mice while having a child? What steps have you taken to clean your house to ensure you’ve gotten everything?