I’ve run into a couple things that I’d see advertised or hear about and think, “Naw, I’m sure it wouldn’t work.” Then, usually when actually needing what the item purported to do, I actually gave it a shot, I thought, “Hey! It actually worked!”
Some examples:
[ul][li]Rug steam cleaners - Surely the folks you hire to do this have the right equipment for the job, and maybe the ones you rent from the supermarket, like Rug Doctor, actually work, but one cheap enough for you to buy yourself? I’m sure it wouldn’t work. But they do! Both friends of mine who have one and the housemates jkusters and thomasm who bought one recently prove that you can get ones that work - and noticably, too.[/li]
[li]Oxyclean - Any product that has its own infomercial is suspect, but sure enough, it works! Got some nasty stains out of our carpet (and thinking of using it with the steam cleaner sometime). I should try it in my laundry…[/li]
[li]Gas treatments - My car was knocking rather disturbingly after a long car trip one time, so I figured I’d try some of this gas treatment stuff to see if it helped. It not only got rid of the knocking, but every time I use one in my tank, my gas mileage improves by about 50%! I fill up the tank much less frequently when I use it, and it costs about $1 a tank.[/li]
[li]Food sealer - I kept opening packages of cookies or whatnot, resealing them in Ziplocs or Saran Wrap or whatnot, and it never failed that by the time I got around to finishing them off, they’d gone stale. So I decided to get a food sealer, shopped around, and eventually got one from a friend who ended up with two in his house and never used it. It’s a little loud, but it works! Yeah, it’s a little wasteful using more plastic bags, but none of my food has gone stale (the real test will be after I’ve had it for a few months, go back to reopen something, and then see if it’s gone stale or not).[/ul][/li]
What kinds of stuff have surprisingly worked for you?
Esprix
Another vote for Oxyclean. I actually haven’t tried it on my carpet (see next paragraph), but I’ve used it for cleaning in the bathroom, and removing mildew from outdoor furnishings. And it did an excellent job cleaning up some old pots (the planting kind).
I haven’t had much luck with carpet cleaners, but Woolite Power-Shot is amazing. It’s like a commerical–you hit the stain with that stuff, and you can see the stain being erased!
Fuel injector cleaner. I started using it about two years ago, and my Jeep hasn’t had a bit of fuel injector trouble since since.
Chia pets–they really grow, and if you get a decent planter shape (like the tree), they really aren’t tacky.
Swiffer products. While they don’t completely replace floor scrubbing or furniture polishing, they do a decent enough job until I really have time for intensive cleaning.
And speaking of furniture polishing…orange oil. I inherited a 90-year-old picture frame from an aunt. She had specified that she didn’t care what I did with the picture (it was ugly!), but she basically just wanted me to have the frame. I thought the frame was a total loss; the finish looked awful, and was so detailed that restoration would have taken ages. At my dad’s suggestion, I treated it several times with orange oil. The frame looks great now–the original paint is still intact, and very vibrant-looking! I had a mirror installed in the frame ($15), and it hangs over my mantle in my living room.
Try Spot Shot – now that stuff is amazing.
Bissell Carpet Cleaner
I’ve always had a low opinion of most aerosol carpet cleaners. Through absolutely no fault of his own, the Zen mutt managed to eject a goodly puddle of liquid excrement onto my carpet. A few applications of the spray removed all detectable signs of the unfortunate accident.
Needless to say (then why say it?), I’m rather impressed and a tin of this stuff is now a regular feature in my household cleaning arsenal.
The George Foreman grill. I got this as a gift last Christmas, and I was skeptical. I mean, really, the boxer/Midas guy is going to get me a decent kitchen appliance? Of course, then I started using it, and anything that can go from cold grill to hot steak in 10 minutes is a winner in my book.
I’ll second Spot Shot and Swiffers.
Esprix
I just tried Nature’s Miracle on an area rug last night.
It really was a miracle!
Now I don’t have to kill my dogs! 
I’ll second the George Foreman grill- it looked so hokey in TV commercials, I’d never have bought one. But I got one as a present, and I use it all the time!
Also… I forget what they’re called, but before our last trip to Ireland, my wife brought home a bunch of clear plastic bags which she asured me would allow us to fit twice as many clothes in our suitcases, supposedly by squeezing out all the air between items. It seemed ridiculous… but it actually worked (though, to be honest, once you grasp the principle, you realize you probably could have done the same thing with trash bags!).
That medicine that comes in the form of droplets. You put them on your dog’s neck, and all the fleas die.
It really works. My dog was literally crying with frustration as she tried to chew the fleas off, and I didn’t think anything could work. I tried flea dip and so forth.
Anyway, the droplets got the fleas, and how.
This sounds nuts… but Loreal Hydrafresh face cleanser. That stuff makes my skin look great, and I only paid $5!! Works beautifully…
I agree with the George Foreman grill too, I used it much more than I ever thought I would.
Oooo, space bags! I had forgotten about those, astorian! I bought one to use for packing up some sweaters; it really does save space. I don’t know how it’s fared–the top hasn’t popped up on the chest where the bag is stored, so I guess it’s OK.