But sometimes things get to the point where they need a proper clean. Connectors pick up oil and grease and dirt, and things like circuit boards can get wet and even suffer from corrosion. The cleaning product of choice for a lot of technicians is compressed air. But while compressed air is good for removing dirt and dust and bigger chunks, it won’t do much for the likes of oil and grease and corrosion. Also, compressed air can sometimes even have a hard time removing baked-on dirt. Others use isopropyl alcohol, which does work pretty well, but you do need to use it in conjunction with a brush or cloth most of the time. Lately, I’ve been using WD-40s specialist contact cleaner spray, and I’ve found it to be excellent. Note that this isn’t the WD-40 penetrating oil that people use to loosen rusty bolts and stop hinges from squeaking. That’s different stuff. WD-40 specialist contact cleaner spray evaporates without leaving a residue and has been designed to be used on sensitive electronics and electrical equipment. Also: Repairing broken plastics? This stuff is better than superglue Unlike compressed air which just blows away debris, contact cleaner will remove oil and dirt and grease and condensation, and even help in the clean up of corrosion (although it is a good idea to have a brush handy – a toothbrush that you’re not using in your mouth works great). It’s great stuff. It cleans well, dries fast, and doesn’t damage most materials (if in doubt, carry out a small test). I’ve found it great to use on even complex connectors, like Apple’s MagSafe connector for the MacBook. It’s the perfect cleaner for the modern technician. You do have to be a bit smart with it, though. After all, you are spraying a highly flammable cocktail of solvents, so read the instructions. It’s all basic stuff really. Don’t spray it on flames or onto hot surfaces, or into your face and eyes. Work in a well-ventilated space, and don’t spray it into gaps and cavities where it might not have the room or airflow to evaporate. Oh, and make sure to disconnect the power to things before spraying, and make sure it’s evaporated before switching the device back on. I also wouldn’t spray it onto displays, as solvents can get between the layers and damage them. Also: How to clean any flat screen TV or monitor If you don’t want to use a toothbrush in conjunction with the contact cleaner spray, I suggest using flux brushes. You can pick up a pack of 25 for well under $20, so it’s no problem to use a new one when the old one gets dirty. These are great for removing baked-on dirt and the green corrosion that electronics get after exposure to water or a broken battery.