K.P.
Have you thought about making it fun for him? I mean, he's a 5 yr old. They don't really respond well to nagging, yelling, or anything like that. Make it a game. Set a timer and tell him to see if he can beat it. When he beats it (and he will because kids love that kind of thing) make a big deal about it. Hug him and tell him how awesome he is for going so fast. You can also make a fun colorful chart, and every time he beats the timer he earns a sticker. After he earns 5 stickers, 7 stickers whatever, he gets a special treat like going out for ice cream, or he gets to pick a movie at the rental store. Something like that. You can also get a very cheap little, kid friendly radio in the toy section at Wal-Mart for his room to listen to while he cleans. My kids love to listen to music while they clean up. Don't you? Just get creative and make it fun. You will get better results from him. You will be happier, and you will have a happier kid.