I have read a couple threads on here as well as other car sites about using vinegar to remove acid rain spots.

Has anyone seriously seen this through and had luck with it? On a black car?

 

Vinegar works well on fresh waterspots because it neutralizes the minerals...I'm not sure about acid rain.

 

doesnt work...tried it.

 

polishing is your best bet ... and sometimes acid ran etches thru to the colored coating. It is very damaging, and very hard to stop. Keep a car well protected is the only option.

 

wouldn't waste effort on vinegar - have tried it many times, no effect.
I agree with Killrwheels - when you really let the water sit on the car, even for a few days - only an abrasive will take it off.

My formula:

• new spots - few days old = Meguiars Scratch X
• baked in for weeks (i.e. actually etched, eroded into clearcoat) = 3m 39002 with orange pad and PC

 

i always use a vinegar solution (1/2 cup white vinegar per gallon of water) after washing my black z06. i wipe each section, or panel with a saturated microfiber drying towel prior to drying. i never have a water spot problem.

 

Removing etched (below surface) water spots from glass--- are caused by acid rain or industrial fallout causing a chemical reaction, if left for any length of time they will etch the paint film surface leaving a concave circular mark. Etched water spots are one of the most difficult paint defects to remove so be patient as it will probably take more then one attempt to remove them.

These can usually be removed using detailer's clay to remove any hardened surface deposits and then using a mechanical type abrasive polish (Zaino ZPC Fusion) with #0000 synthetic steel wool or Iz Einzette Glas Polish, a random orbital buffer (speed # 4) and a cutting foam pad (LC orange or yellow) to level the surface.

Notes:
Do not use abrasive cleaner; glass polish or any grade synthetic steel wool on after market-tinted glass or you will probably scratch the surface.

1.For deeply etched water spots' in the glass surface, do not attempt to polish them out, consult an automotive glass vendor as glass used on later model cars is soft and thin (this may vary by manufacturer) due to weight / cost savings by vehicle manufactures and polishing could cause glass to crack.
2. Be cautious with polishes that contain abrasives like aluminium or cerium oxide as they have the potential to damage glass beyond repair.
3. Some windshields and mirrors have a tinted plastic coating or a blue tint that will scratch or be damaged, only polish or use synthetic wool on uncoated glass.

 

What makes acid rain 'etch' paint and / or glass sufaces-

Reactivity [: acceleration of a chemical reaction by a catalyst]
Like any chemical attacking modern high solids paint, there are some variables;
what type of clear coat, the older 1K's, 2K, or the newer 1K, colour of base coat will dictate surface temperature reactivity (acceleration of a chemical reaction by a catalyst [moisture, heat] )The higher the skin temperature of the surface, the quicker the reaction(reactivity) takes place. The percentage of humidity that is present, or dew, as an oxygen molecule will create an environment to facilitate the acids to cause damage.

Cool weather, no direct sunlight (therefore a lower surface temperature) a lighter base coat colour, sometimes it could take days or under the right conditions, the paint could be subjected to surface "etching" can take in a matter of hours.