Some people say you can make a clean room at home, in the bathroom, by opening the hot water faucet and filling the bathroom with steam, and at that condition the air would be totally clean and you would be able to open the drive without damaging it.
This myth was very well elaborated, but it can also have unpredictable consequences for the data. Have you noticed that when the sun comes out right after thin rain the air seem to be cleaner? And it is indeed, because raindrops have made the dust in suspension go down to the ground. Hard disk greater enemies are dust and humidity. That's why they can only be opened in a class 100 clean room (where there can't be more than one hundred dust particles larger than 0.5 microns in any given cubic foot of air).
And someone thought: I turn on the bathroom heater in maximum for some minutes, then turn it off and wait for the small drops to come down until the air gets "clean". Then I open the hard disk and touch some parts, poke it, nudge it, or even replace the platters.
Well, although it's a good Idea, the result is a disaster. Very sophisticated equipments are used in a clean room in order to manipulate hard disk's parts, under controlled temperature, pressure and humidity. All this because we can't risk making things worse, we have to save important data. If you don't know what to do with an open hard drive and don't have the proper tools to deal with it, be sure something very wrong will happen! But we always give luck a chance - it also works!
