Start With the Inside

Once you’ve gathered your tools, it’s time to start cleaning the inside of the computer. Tackling that grime on the keyboard may be tempting, but Ms. Kerr said you should start with the less glamorous internals: “Canned air will blow crumbs and cat hair and what-have-you everywhere, so if you’ve already cleaned the screen and bezel, you’ll just end up having to clean them again after you’ve used canned air.” Start by blowing out the dust, then move on to the outside.

Provided you’ve maintained your laptop well, you shouldn’t have to open it up for this step. Just turn off the laptop, unplug the power cable and remove the battery (if it’s easily removable). Grab your compressed air, give it a quick burst away from the laptop to get rid of any condensation, then start blowing air into any cracks and crevices: the keyboard, the vents and even the USB ports. Blow in short bursts, since longer sprays can cause moisture to accumulate inside your computer and can damage the fans by making them spin too fast.

If you’re lucky, you probably won’t see a big change after doing this. The goal is to prevent dust buildup over time, which can cause your laptop to overheat. If there are visible dust bunnies in the vents, you’ve let it go far too long without a cleaning. In that case, you may want to open it up (if you’re comfortable doing so) or take it to a repair shop for an in-depth cleaning. Smokers and pet owners should take special care to clean the inside often, since you’re likely to experience much quicker buildup of dust, smoke, hair and other particulates.

Wipe Down the Outside

Next comes the fun part: making that laptop shine again. “The most critical thing when cleaning a laptop or desktop computer is to apply the cleaning product to the tool you’re using to clean, never ever directly onto the computer,” Ms. Kerr said. So grab your microfiber cloth, pour a few drops of alcohol onto it, wring it out so it isn’t dripping wet, and go to town on the surface. You may want to use cotton swabs and alcohol for the keyboard keys and the small spaces between them. (If there are marks that won’t come off, you can try rubbing them with a Mr. Clean Magic Eraser very lightly, but again, they’re mildly abrasive and this can alter the finish of the surface.)

It may take a few passes to get all that grime off, but once you do, you should notice a dramatic difference. If your laptop is particularly old, you may not be able to get rid of the shine on the keys; some of us may type like the Incredible Hulk and have worn down the top layer of plastic. There’s not much you can do about that.