Dust filters

Hi. I own a Dell G15 i5-13450HX, 16Gb, RTX 3050.

Dust filters, the ones on top specifically, are dirty and needs to be cleaned. Until now, I've been cleaning them using a brush from above only and have never unscrewed the laptop, but now i don't think they can be cleaned superficially because the dust is stuck on the filter and doesn't come off easily with a brush. I've never opened a laptop myself (also i don't know if it can or cannot void my warranty) so I don't wanna take any risk. 

Can anyone provide me with methods to clean it myself?

Or should I approach the service center and let them clean it?

Also,

are replacement dust filters available and are they covered in the warranty (Premium Support) ?