Here in the Denver area, they use Magnesium Chloride on the roads to clear the snow from the roads in the winter. This is pretty nasty stuff (and it doesn't work all that well removing snow, either). On my last car, I started noticing brown spots on the chrome bits, that I couldn't remove. When I went to the dealer for a different reason, I asked about the spots that he become really noticeable to me after 3 years. He laughed, and said it was the mag chloride. There was nothing I could do short of replacing the bits.

After hearing this, I started making a strong effort to wash my wife's new RX after every snow, to get off any mag chloride residue. I also went pretty heavy with a sealer on the chrome AND the paint, hoping to add a little protection. Although it seems to slow down the damage, I noticed some small spots during my spring detail and cleanup.

Is anyone aware of anything else I can try, to minimize this issue? Is there anything that has a shot at removing the existing damage? I have a new IS that I really want to keep nice!

 

I'd like to know this as well. My SRT8 had the same brown spots on the front grill; I ended up buying a new grill & got it clear bra'd.

 

Nearly all de-icers on the market are made from one, or a blend of, five materials — calcium chloride (CaCl2) sodium chloride (NaCl) potassium chloride, magnesium chloride (MgCl2) and urea. What makes these products different is how quickly they work and at what temperatures. This is determined by whether the de-icer releases or absorbs heat upon contact with snow and ice. (See also article Corrosion (Removing Road Salt)

Removing Salt from Paint Surfaces

Road salt removal is difficult to remove as many State authorities use an additive based on molasses, a bye product of the sugar refining industry, to ensure the salt solution adheres and is therefore more effective. There is a product formulated by Optimum™ Polymer Technologies; Opti™ - Clean that is effective in removing salt, etc from paint surfaces

Waterless polymer based systems do not require pre-wetting the surfaces. A combination of polymers and surfactant cleaners that encapsulate and safely remove salt, dirt and grime and leaves a glossy protective finish. The polymers and surfactants used in these no rinse washes have the capability to bond to dirt particles and act as a barrier between the dirt particles and the paint. The salt, grime and dirt is then trapped in the surfactant, protecting the paint finish with no need to use a large amount of water to flush the dirt off the vehicle.

Undercarriage Cleaning & Care

Your vehicle’s undercarriage; it’s what you don't see that silently awaits underneath your cars. Removing sprayed brine solution to protect your undercarriage is just as important as detailing the paint. Wheel wells, sub-frame, springs, fender well and all of the other black and gray parts underneath the body need detailing too.

After removing dirt, road grime, and etc with P21S® High Performance Total Auto Wash or Optimum™ Polymer Technologies - Power Clean- use a pressure washer (Kärchar Model K5.700) neutralise the effects of the alkaline sprayed brine solution on the suspension, wheel wells and the undercarriage (See also Road salt)

 

Idk if this would be helpful but, I try to rinse the underside at the pay to wash places during the bad weather times and I ended up plastidipping my front grill before it formed spots. I too have spots and staining on my tanabe exhaust and I couldnt get them out. I just ended up exchanging exhausts for summer and winters. Rinsing during the mag chloride days goes a long way though...

 

Opti-Coat 2.0, A-Quartz or C-Quartz will prevent the brown spots on metal. I use Opti-Coat 2.0 on my personal vehicles here in WI where we have a lot of snow and the same salt control products as you do.

Polish the metal with a metal polish then wipe down with a 50-50 IPA mix prior to application.

These products offer permanent protection and don't erode over time like sealants or wax. They are also several times thicker, providing great protection and longevity. It takes an abrasive polish to remove. They will not wash away with Dawn, or even Prepsol.

I also am a big fan of using a touch-less wash in the winter slop especially for the under body flush. I have a 91 MR2 that was a daily driver here for 12 years and there is virtually no underbody rust on it. My 04 Rx330 likewise has no underbody rust. Another plus of using Opti-Coat 2.0 is that the harsh detergents at these touch-less washes don't degrade the coating one bit.