Looking to sell your vehicle? Many consumers are so emotionally invested in their vehicle that once they decide to replace it they no longer make the effort to keep up its appearance. That could be a costly mistake.

Making the effort to get it spruced up; washed, waxed and vacuumed, could be one of the smartest things you do to maximize its value, according to Alec Gutierrez, manager of vehicle valuation for Kelley Blue Book.

He says the difference in the value of your car as a trade-in could probably be negotiated upward by an extra $300 to $500 if it's properly cleaned. And some say that if you're selling the vehicle privately, it could mean even more.

Lauren Fix, otherwise known as "The Car Coach"
'The Car Coach' says that making a maximum effort cleaning up a mid-range vehicle could yield considerably more in a private sale. "It all depends on the actual vehicle... You might have a vehicle that isn't even worth $2,000, but on the other hand you might have a Mercedes or a BMW and for those high-end vehicles it's conceivable that cleaning it up well could add as much as $2,000 to the price." But she concedes that most of us are not likely to see that kind of windfall...

Fix notes that for the average passenger vehicle it's still a good idea to take care of the little things one can fix or repair easily such as a burned out headlight or taillight. She strongly recommends cleaning up as much as possible, especially dingy looking headlights that can make your car look worn out. Auto parts retailers have a variety of products and kits ($15 to $50) to expedite the process.

If your car is worth more than $40,000 you may be better off paying a professional auto detailer to clean it up thoroughly. That way you've ensured the maximum return on your investment. And if it's just another jalopy, that's OK! Cleaning it up will still get you the best price.