Have you ever noticed the difference in your feelings toward your car right after it has been cleaned? It looks great, doesn't it? Yes, it does. When the appraiser looks at your trade it's going to look much better to him as well. if its clean. And if your car looks better visually then the value is easily increased in his mind because the condition looks better.
It is really simple. If you spend a little time detailing your car or have it done professionally for forty or fifty bucks you can literally add $300-$500 in value to it! It sounds excessive but it is really true. When you check the value on a third party website like Kelly Blue Book (kbb.com) or Edmunds.com a clean car can really push the line from "good" to "excellent." This is most especially true when you are selling the car on your own. A clean car will get you more traffic, more interest and in the end more money. Car buying is an emotional process and when people who look for a new(er) car they tend to be able to picture themselves in a car much easier if the car is clean. And getting a buyer to connect with the car and see themselves as the owner is the first step in getting them to buy it. Just think of the last time you bought one. Did you see some that were dirty? Not as appealing were they? When I see a dirty car it makes me question if they maintained the vehicle properly. A clean vehicle shows care by the owner and I always feel more comfortable buying one that is clean because it makes the owner of the vehicle seem more credible and responsible.