Children are disgusting. They are so disgusting that if these people weren't born of your very own body, you would not touch them with a ten foot pole. Personally, I think that they are disgusting as part of an evolutionary plan--their only natural defenses are being both cute and gross. Your baby smiles at you so you don't abandon her at the grocery store. She poops on you to ward off jackals.
Unfortunately for you, they don't really seem to grow out of it. I have seen my daughter lick both the bottom of her shoe and her hand after touching a public bathroom. That latter event was willful--I was saying "don't touch anything, don't touch anything" as a kind of OCD mantra when she put her hand on the wall of the stall. I grossed out so she licked her hand. Serves me right.
Your 6-year-old will spill milk in his room and fail to tell you until maggots are growing in your home. Your 9-year-old will go swimming in a lake in his underwear, let them dry out, and put them back in his drawer because they seem "clean" to him. All children ages 11-13 are so repulsive that educators put them in their own schools in most parts of the country.
As a teenager your sweet daughter will share her lip gloss with her friend Jenny because Jenny's lips are cracked and she usually borrows her boyfriend's chapstick, but they just broke up because Jenny found out he's also been dating Mandy the Slut and they were caught kissing at a party last night and Jenny is so upset, how could she (your daughter) NOT share her lip gloss? It will not occur to your little girl that she has just shared germs with Jenny, her boyfriend, Mandy, and whoever else Mandy has been kissing lately. And don't even get me started on the teenage drink-sharing phenomenon.
Your only way of dealing with the nastiness is to coat yourself in hand sanitizer. Carry it in your purse, your glove compartment, and any other vessel you can think of. Buy gigantic refill bottles of the stuff. Boil things on a regular basis. One day, when they don't live at home anymore, you might have a clean house. By then, of course, it will be the eerie quiet that will drive you nuts.