Hi sifu-situ sekalian, tumpang tanya

So I upgraded from X to 13 Pro Max last month.

All is well, but I noticed my 13 is starting to collect what I would think are my sweat residuals at the microphone location on top of the FaceId module.

To be exact, there are white specks caught between the seam between the steel border and the microphone.

Any idea how we can clear these unsightly stains? I tried using cotton bud and my gf’s makeup brush (a new one) but to no avail.