Extreme GPU cleaning ?

[Anemuron]

Hello guys

my question is about cleaning graphic cards, I know the basics and I know how to clean my heatsinks and fans very well but I am looking for a safe-if-you-know-how way to clean the surface dust that you can see on graphic cards after some time

Is there such thing ?

I can provide pictures later if I am not clear about what I am reffering to

 

[Anemuron]

Paint brush + vaccum seems like it could do the job well, do you think that if I put enough work I would be able to clean it to new-like condition ?

I want to sell the card to one of my friends and he's really superficial and this thin layer of dust makes card appear a bit grayish which he will interpret as hundred years old and will be reluctant to buy. (the card itself has been taken care of, it was running on aftermarket cooling at 55 degrees full load and it was cleaned often, never OCd)