imageHere’s a nifty little tool you might want to stick in your pocket or purse for when you’re checking out a property: An ultraviolet flashlight.

They cost less than 10 bucks, and they can be quite an eye-opener.

What do they do? They make bodily fluids glow green. If you’ve watched CSI you’ve seen them at work, although you probably won’t be looking for blood (or other) stains after a murder.

I got one of these from the good folks at Battery Junction. (I can’t praise the store enough. Good prices, great selection, and incredible customer service. And no, they aren’t paying me to say that.) It uses AAA batteries and should last virtually forever.

First use: Check out my nine-year-old’s bathroom. I turned off the main light, shined the UV flashlight around the toilet, showed him what I saw, and instructed him to clean. (He was not nearly embarrassed enough, in my opinion.)

But what made me realize the value of this as a Realtor tool was when I took it to the carpet downstairs. We have dogs and cats, and they, sadly, have accidents. I figured I could find any spots that needed attention and take the carpet cleaner to them.

Well, the previous owners also had dogs, and apparently also had issues. Because I found not the few spots I imagined, but lots. And lots. Green glowing sections all over the place — more so than our animals could have made in the few months we’ve been here.

See, the UV light detects these things long after they’ve dried. So what appeared to be a beautifully clean carpet turned out to have, well, a history. imageAnd this was after multiple uses of a carpet cleaner. Scary, huh?

What this tells me is that I need to get hold of some serious Nature’s Miracle, which should actually break down the long-dried urine and let me clean it out for good. Luckily, there’s no way to tell these hidden stains are there without the light. There’s no smell — but now that I know they’re there, I must destroy them.

So, can you imagine taking one of these lights with you with a buyer? Shine it on the carpet and see how clean those carpets really are.

Oh, and heavy-duty versions of these lights are used by some hotels, too, to make sure the rooms are really clean. Still, I’m taking mine with me next time I stay in one, although I’m afraid to shine it on the bedspread.

Meanwhile, The Boy’s bathroom is clean, although he says he’s never going barefoot in the house again.

Click here for the light I bought — it’s $7.95 with discounts if you buy 10 or more. Brokers take note.