[frzntax]

Despite a few good washes, I can't seem to get these spot stains out of the fake chrome side mirrors (also similar is visible on the front grill accent). Not sure if it's water, or maybe even mold? They aren't raised or textured, just stains. Any suggestions? Even considering side mirror caps because I catch myself looking at them while driving an otherwise shiny car.

[DBO]

So only on the plastic parts then .. sap or tannin from a tree perhaps? Have you tried a mild paint correction cutting compound & polish?

[Jas387]

If you are confident that they are water spots, a number of companies make water spot removers you could try - CarPro, Chemical Guys and GTechniq to name a few.

[Nadz]

Originally Posted by DBO

So only on the plastic parts then .. sap or tannin from a tree perhaps? Have you tried a mild paint correction cutting compound & polish?

I would try this. No need for a DA - try hand polishing it out with a compound and as usual - start with the least aggressive compound first.

It may also be worth trying to clay it and see if that makes a difference.

[MauiSteve]

I'd try a gentle hand polish using a microfibre towel and some Sonax Profiline Perfect Finish. That's a light cut polish which is clear coat safe. It should get those cerium grey side mirrors and other trim parts looking new again.

After the cerium parts are looking good wipe with some 70% isopropyl alcohol or Carpro Eraser, then coat with a protectant like Adam's Graphene Ceramic Spray which will give you lasting water beading protection.

[frzntax]

Good tips! Yeah, I can't say for sure what the origin is - car came with them, and I have it garaged. After some gentle hand polishing, the main "spots" are removed, but now exposed is an even deeper stain pattern. Will try some clay next.

[DBO]

Is it both sides or just the one? I'd almost go see the dealer about that to see if there's any potential fault in the coating.

[frzntax]

Yes, it is the case on both. I'll be by a dealer tomorrow and swing by to see what they say.

[jsf721]

Use some finishing polish or tarminator Will come off easy. Looks like tree sap that attracted dirt to me. Then just rinse and wax or coat.

Where are you located. If your on Long Island I can assist.

[Warp Ten]

Could be acid rain. Do you have similar spotting elsewhere on the car? I was a skeptic at one point but then found I had the problem also. I remember that we also had acid rain problems at the BMW dealership if cars sat on the lot for a long time. I got a lot of it out with polishing compound but I don't think that I ever got it all off. My guess is that a good detail shop can clean the up for you. --Bob

[frzntax]

So after showing this to two different dealers in different parts of the state, the automatic reaction from both was "that's normal, they all do that." Apparently this is remedied in new model years (not sure if 2020 or 2021) because of so many complaints that BMW has received. I recently test drove some other M550s and they all exhibited this to a varying degree, but I think what I have pictured is more of an extreme case - especially after doing a deep clean and exposing some more layers of whatever may have been etched in there by the previous owner.

[MauiSteve]

That stuff should polish out with the Sonax as I mentioned above. Did you even try?

Ya know, I've never been a fan of the cerium grey trim pieces that came on the M550ix. If those mirror caps really bother you and you want to be rid of them forever you do have several options of new mirror caps on e-bay.

Here's how easy they are to change out:

https://www.youtube.com/watch?v=6Rl_r22MhsY

[frzntax]

I actually held off on Sonax or anything further, because I ended up swapping to another M550 that came up for sale recently and hit all of the desired build options. While of course the trim pieces still hold water spots, there isn't that underlying stain pattern evident on these (I intend to keep it that way, although still considering side mirror caps for cosmetic preference). Thank you for the help!