Rep Power: 0

(Did a search, both on Google and here, didn't find much.)

1-2 months ago or so, I noticed a spatter of small rust spots on my driver's side mirror. This morning I noticed they seem to be getting worse. See pictures at bottom (can add larger ones if needed)-- it looks like someone splattered a rusty milkshake on my mirror. The passenger side is fine.

Any ideas? I know mirrors have a metallic finish on the back, but these spots are on the front (I've not tried removing the mirror to look at the back of it). I'm pretty sure it's not just something ON the mirror; I tried scraping a couple with my fingernail and they definitely seem to be... rusty mirror spots.

Of course, just because I've never heard of this happening before doesn't even necessarily mean it's uncommon, but... I've never seen this happen before. What might cause it?

(A note: I did have some bodywork done a couple months ago... before I noticed this, I believe. It was just to repair some body rust and didn't involve the mirrors. But I thought I would mention it in case it might somehow be related? It's the only thing I can think of that might even remotely have caused this-- that is, the only thing my car has done out of the ordinary lately.)

Thanks in advance.

 
Rep Power: 518

If you can scrape it with a nail, try scraping with a razor blade.

 
Rep Power: 0

Interestingly enough, I can scrape much of it away with the blade. However, in the center of each spot is a tiny piece of gritty stuff that I can't scrape away (somewhat visible in the picture). Tiny-- I'll need to get out my jeweler's loupe to really see them. These are perhaps tiny bits of metal that are rusting? I'm trying to recall if my car has been in any situations to get sprayed with dirt/grit hard enough to embed it in the mirror or something-- truck spinning out near it or something. I can't think of anything. Weird. But at least it makes me think the rust is from whatever these little specks are, rather than the mirror itself (which means a mirror replacement probably isn't in my future-- just keeping it cleaned up).

 
Rep Power: 518

Was bodywork done on that side of the car? That door or the rear door?
All I can think of is grinder sparks that hit the glass, possibly causing pits in the glass.
I don't know if that would actually cause your problem or not, but you mentioned bodywork.

 
Rep Power: 0

Yeah, there was some work done on that side. Not sure, either, if that's the reason, but... very strange.