Kids are sponges. You can literally use them to mop your floor, and then squeegee them against your windows for that final finishing touch.
Oh sure they might cry, but that's all just part of their rapid learning process.
Yeah, i know! Its great... never where my windows that clear and my floor better mopped. The only problem is that the misses gives me strange looks since i use junior this way and for some reason this annoying child welfare officer is now constantly visiting...