How do you clean a heatsink?

I just installed 720qm to my gx740, how do you actually clean the heatsink? I don't have compressed air, Is it ok to clean it with water or soap? and how much thermal paste do I need to apply?

 

DON'T use water. are you nuts? that's conductive AND corrosive.
You just want to remove the dust, just blow into the fins. clean it with a tissue. compressed air is really great... and cheap. just try to buy a small can. it will make the job much easier.
about how much paste... well just the same amount as it was when you removed. don't apply too much that will make it spread to other components but make sure you apply enough to cover the gpu. make sure you properly assembly the gpu to the heatsink. it must be absolutely parallel otherwise it won't work properly. Also if you are unsure how to apply etc just use a non conductive paste just in case.
you have hundreds of videos on youtube about how to apply thermal paste.

 

Well just now i was searching and I read something about putting it in a dish washer but it was a desktop forum, it cost 10-20 dollar for compressed air, for the thermal paste I did google it but I get so many different way, the as5 instruction is using spread method, but many people in the forum said it was bad, etc, etc. for the thermal paste does it need to cover edges to edges?

 

use a soft paint brush - works perfectly for the heatsink fins. Alcohol and any cloth/tissue for the contact surface and that's pretty much it...

 

Poster #2 is correct, don't use water-based solutions to clean a heatsink or any internal part of a computer ...

I use Isopropyl alcohol to clean heatsinks (assuming we're talking about the part that is covered in thermal paste). Clean it with a paper towel or microfiber towel.

The use of thermal paste - first understand that you should use as little as required to accomplish its purpose of filling in tiny gaps between the processor and heatsink surfaces. This facilitates the thermal energy transfer between them and prevents air bubbles (very bad).

That said, I have used both the AS5 method of spreading it and the method where you simply place an amount on the processor and press the heatsink down upon it. I haven't gone wrong with either method. Just get the amount right.

 

I use this to clean the paste residues. Works great.
Arctic Silver Incorporated - ArctiClean

There's several methods to spread thermal paste because there's different kinds of it. any method will do. I use a plastic sheet or gloves and spread it with my fingers. also, arctic silver is conductive.

 

Option 1: Remove the heat sink and putting under a tap with running water to remove the dust stuck between the fins. Let it dry for a bit and reinstall in inside the computer.

Option 2: Remove the heat sink and use an old tooth brush to clean the dust off it. you can also use the tooth brusk to clean the dust off the fan.

Note that above I said to put the heat sink under running water and not the fan. I usually use kitchen paper roll to clean the old thermal paste before putting a new layer and that works perfectly.