Chemical Guys waterless wash is pretty good for bird bombs. I did have some serious bird crap that wouldn't come off. I resorted to Sprayway glass cleaner, mf towel and a plastic interior trim tool.
I recently used a clay mitt on my car. I didn't think too much about it since I was using it with soapy water. This mitt was several years old and left some scratches. As for iron decons I guess it depends on the environment. If you are near industrial areas it would probably be worthwhile to...
I know back in the late 90's a lot of white vehicles had issues with peeling paint. I suspect the ongoing paint issues have to do with VOC compliant ingredients that aren't as good as previously used products.