My Kindle Fire is a typically featureless black slab with one button, two small speakers, and no fasteners. After a few days in my pocket, the upper-left corner began collecting dust on the inside face of the cover glass:
That’s not terrible, but it does look ugly and lowers the contrast a bit in that corner. As nearly as I can tell, the speaker grilles provide the only way for that dust to get in, although this was a refurb unit and perhaps the seal around the rim is broken.
In any event, the speaker grilles look like this:
I slapped a strip of 3M Micropore tape over the openings as a stop-gap fix:
After a few days, the dust wasn’t getting any worse, so I ran a scalpel blade around the speaker opening and sank the tape atop the grille:
The advantage of Micropore tape is that it won’t completely block the already feeble sound from the speakers.
The Smell of Molten Projects in the Morning 
Since you have 3M micropore tape in your arsenal that’s an automatic +5 Geek and and +10 Old School Cool.
Back in the pre-CNC days, it was a good way to put a conformal layout layer on a workpiece: write on it, punch through it, clamp it, drill it, peel it off.
At my current rate, that roll will become a hand-me down.
Old School, fer shure! Thanks for the good words…