I bought a display camera. It had been the display for about a year, out in the open, but without the lens mounted. I think people mistook it for a fingerprint scanner since the sensor was a full of fingerprints, dust and general gunk. It was cheap and the lens was worth more than the purchase price so why not? I cleaned the sensor last night. Yes, I could have gotten it professionally cleaned but at the price I paid for it, it just wasn't worth it. Yes, I could have gotten some of those clean room made sensor swabs but they cost almost $1 each. Once again, not worth it. The way I looked at it, nothing I do to it could be worse than a year of people putting their fingers all over it. I had q-tips (cotton swabs), 99% isopropyl alchohol and and baggy full of pec pads. What more do you need? I made a "sensor swab" by cutting up a credit card and affixing a pec pad to it. I then dipped it lightly in alcohol and swabbed away like you are supposed to with a sensor swab. This turned out to be a major mistake. It ended up pushing the grease from the fingerprints onto the edges of the sensor which ended up being a major hassle. Also, contrary to what some people say, 99% alcohol does leave streaks. I knew that before from prior experience. I then broke out the cotton swabs, dipped them in alcohol and started to scrub. This clean up a lot of the gunk on the sensor, but left a lot of streaky residue as well as the gunk that got left on the edges when I tried to swab. Thinking back, I should have started with the swabs and worked my way in from the edges. There was also this one speck that refused to move. I scrubbed and scrubbed to no avail. I was afraid it was permanent. So I did way I would do if I was out and about and had a stubborn speck on a lens. I got a plush microfiber cloth, like what I use to dry off my car. I then huffed on the sensor and polished it using the microfiber cloth. That got rid of the stubborn speck. It also got rid of a lot of the residue and gunk along the edges. It was looking pretty good. To finish it off I made a micro swab using a further cut up credit card and the pec pads. I use this to swab down the sensor with alcohol again. I then boiled a cup of water in the microwave and use the steam from that as a source of distilled water. I moisted up my micro swab with this steam to rinse off any of the alcohol residue. In the end, it turned out pretty good. I wish I had taken a before picture of the sensor. It's not my first time playing with sensors. Yes, I know it's not the sensor but the AA filter over the sensor. Contrary to popular wisdom that says that the "sensor" is so delicate that a flea fart will permanently damage it, I know that the glass covering a sensor is more or less the same as the material used to make a filter or a lens. It's a lot tougher than many people think. I ended up doing pretty much everything the "professionals" tell you not to do. I did forego the scotch tape though. That's just crazy. The proof is in the pudding. Here's the pudding. A couple of shots from the backyard. NEX-3    E 18-55mm F3.5-5.6 OSS    25mm    f/8.0    1/500s    ISO 200 NEX-3    E 18-55mm F3.5-5.6 OSS    55mm    f/7.1    1/200s    ISO 200 I don't know why I was surprised, but the camera had never taken a shot before. It started out at number 1. Considering that the camera was displayed without lens, no memory card and most importantly, no power, that should have been expected. As for how clean the sensor is, here are some dust maps. Here's one taken at F22. This shows the dust most clearly. There will be a original shot where it's hard to see the dust and then an enhanced shot which makes it easy to see the dust. Original Enhanced to show the dust. I know that it looks like a lot of dust, but I've seen worst even from clean cameras. You might not think your camera has dust, but I can guarantee you that your camera has dust. Here's a shot at F8. Original Enhanced Much less visible.