First pick out the dust by bare hands then blowout the dust with some blower. Make sure the power cables are plugged out.
I am not sure but I have heard to refrain from using any kind of blower cause it can lead to formation of static current on the PC which might damage the chips on the MoBo or GPU !
Then How will you remove away those tiny dust particles. Please let us know if you have any alternate solution
Use a paint brush which has gentle bristles. Thats how I like to do it.