can i clean pc with wet paper?

on outside? sure... as long as nothing drips/seeps inside the case, you are all good. The case will keep whatever little moisture is left on the outside.
Inside and on components? I wont recommend it at all even if powered off.

Not that you usually even need moist towel, the dust is pretty dry and wont usually stick to the case unless some other adhesives are used like... sugary soft drinks or something.
 


how would i clean the inside of my case
 


lol, where would i blow it though, i can't blow from the inside to outside, if i just blow it, is gonna be further into the case xD
 
I can guarantee that >90% of it will float outside the case.
Which usually means that you should take the case to somewhere where said extra dust on air/floor wont harm anyone. Outside is usually pretty good choice.

as example:
you use pressurized air can. (or leaf blower like someone in youtube video's do, I do not recommend this though) and give CPU cooler a short burst.
Said dust in cooler will get blown free and flies outside the case or remains as a dust could.
second short burst past the cloud, on the mainboard, pretty much pushes what remains out of the case.
Rinse and repeat on PSU and GPU and other toys as needed.
 


do i have to take everything apart and do it individually