Dust on your iMac late 2013 display? May I use this?

Hi, I´m a school user of macintosh witch after 20 years buy an iMac late 2013 with a gtx775m to play games like wow, lol, gw2, etc on his computer, the iMac in fact isn´t built for gaming but i don´t know they were not capable to support dust, as you can see in the image there are some dust in the down corners of the display.

i can wash it, so i have to make a few dollars filter with a kitchen extractor filter and a 2x2 cm aluminum squad, as you can see in the others images,

front view:

left view:

I also use masking tape and zeal to link it to the imac, very light and efficient, this compensates for the lower absorption capacity of the filter with a larger surface area makes the fan speed does not shoot because it is not able to absorb the necessary air.

The questions it simple ¿Are there any other option to stop dust better that this or just change the display? It isn't serious this design have this error. Also i think would be Helpful for most of the users, the cleaning Campaigns because the performance will be compromised if the internal filters are dirty. I clean it with a straw and a vacuum before put this filter.

Thanks a lot.