Okay, here's a question. There's a small black spot on the screen of my 67A750, close to horizontal center and about 2/3 of the way up the screen. If I look closely at it, it looks a bit taller than it is wide, and doesn't seem to be pixel-shaped; it seems to be just a bit bigger than the surrounding pixels. It's barely visible from a normal seating position, about 8' away, but once I notice it my eye keeps getting pulled in that direction.
Is this a dead mirror, or perhaps something on the lens? What's the best way to determine that? If it's something (dust, grit, etc.) that can be removed, then what's the best way to go about doing that?
Apologies if these are elementary questions; searching for this sort of thing brings up a ton of discussions of white dots, but not so much about other artifacts. Thanks in advance for the advice.