Exactly distributing a graphics card to clean it is no big secret, but if you don't have the knowledge, the synthetic materials (you've got the hot ones) or if you don't you have lost the warranty (As most manufacturers withdraw when you separate it) you'll have to solve it by cleaning it up more, so that you can leave it really nearly the same (unless, of course, the time comes and you have to change the hot paste).
Prerequisites
There will actually be three things to clean up the graph without separating it: a compressed air computer, drainage drainage drain
How to clean a graph without dividing it
The first step should always be to apply compressed air force, since it will remove the excess dust and, in particular, the accumulated soap between the heatsinks in the graphic.
If your graphics card is a blower type, make sure you do NOT want to use compressed air from the back of the graphics (where the video comes from), because with that you will press the dirt again. Instead, all you need to do is aim the edges of the fan, so that the air goes inside. If you do it right, you'll notice that the dirt comes directly from behind the graph.
If your graph is not kind of spirited but has regular fans, you should apply compressed air from the top to get the dirt out of the floor, making sure to use it throughout the graph pan to try to clean everything inside the heatsink.
Next step Use wet victims to clean the entire surface of the graph, with special attention to fans and to its low point, is where pollution accumulates. To do this you must keep your fingers dry, taking care not to keep the fan too tight. If a slight bend is not possible, that plastic is flexible, but be careful that they don't bend too much or you can break them.
The last step, most importantly if the graph is not a blower type, Use the ear buds to clean the grill back. If you want you can slowly lighten the rods with isopropyl alcohol, but it is not necessary because you simply eliminate the dirt that may have been in the machine after removing it from the compressed air.
With these three steps, he will have realized that cleaning a graphics card without having to assemble it is not a complicated process at all, and, in fact, you should do it at least once every six months. Changing the hot paste is a very difficult (but not complicated) process, and you can leave it completely for 2-3 years without a problem, when the image is still validated.