I`ve tried
Optimum`s Car Wash (soap) , but it did not "work" well with our Lake Michigan limestone-laiden sourced Green Bay municipal water and left streaks behind when it dried on the windows. However, I must blame part of that problem on myself , as drying my vehicle with a leaf-blower may be the culprit and then wiping the windows with a less-than-quality drying towel. I did try mixing
Optimum No-Rinse with it to mitigate this "problem", but it seemed kind of counter-intuitive for a 2-bucket wash and was just not cost-effective. It`s cleaning-ability is very good, especially on road film.
I have been using
Meg`s Detailer Line D110 Hyperwash after seeing Autopian All-Star RaskyR1 use it in his detailing business, and it has worked OK for me, even with our municipal hard water. The suds last FOREVER!
My favorite wash though is
Meg`s Professional No. 62 Carwash Shampoo and Conditioner. After reading that a major car museum used this for its collection, I thought it would be good enough for my daily drivers.
It is still my favorite maintenance soap and works pretty good in hard(er) water. The problem is the cost: about $37.00 for gallon. Compare that to $27.00 for Hyperwash, and its a no-brainer. It`s lubricity is very good, but if you have a lot of road-film, it was not as good as Optimum Car Wash. The smell is extremely pleasant and not too perfumey or fruity.
I also have to admit that for my daily drivers that I wash, using
Poorboy`s Bug Squash to pre-treat nasty late spring and summer bug splatter is almost a necessity and it makes short work of that washing problem, especially when it has been a while since the last wash and those bug guts have dried on to the front bumper fascia or the door side mirror covers. It will not, however, remove the etching that comers from leaving bug guts on paint/clear-coat for too long. I have told vehicle owners to wash the bugs off as-soon-as-possible, even if they use less-than Autopian-approved washing techniques to reduce or mitigate the etching that can and does occur from leaving bug guts on paint/CC for too long. Wash-induced swirls I can get remove; deep etching I cannot.
Also, if you cannot avoid having to wash cars in the sun, I HIGHLY suggest you check out this thread:
https://www.autopia.org/forums/auto-detailing-101-a/187416-soap-sun.html?highlight=#post2105019