It is never to early to teach kids how to wash dishes or how to do a few minor, kid safe house chores. This is sensory activity for them, too. The idea of seeing, touching, smelling, and even hearing the sounds of the water and the dishes as they wash them. Not to mention, they are developing their motor skills!
Whenever I am making a recipe, my toddler always wants to help me make it. And sometimes she just wants to stand at the sink and play in the water with little cups, bowls, and spoons. She will fill, dump, refill, dump, and over and over again. So one day, I had seen a post on one site that talks about toddlers washing dishes. Then I decided to teach my kid how to do so. She really enjoys doing it at least for now.
Of course, I have to tell her you need to wash this part, and that part, and rinse it properly, and even take the soap filled ones from the drainer and rinse it over again, but she is only a little toddler so that is quite OK.