If is truly was "latex", then having the vehicle in the shade and cool, most any "all purpose" cleaner, allowed to dwell and kept wet, would have broken it loose.
A quality "all purpose" that is not "loaded" with butyl cellosolve surfactants or sodium hydroxide components will "crawl" under the paint overspray, as it breaks down the resin system of the latex, and most should come off easily.
There are variables of course, such as "how long on the surface", "was the overspray present when the skin temp of the paint and the air temperatures were very hot", etc.
We often forget that "dwell" time, allowing the products to work is very important to obtaining the required results.
Which is why that knowing some basic chemistry, like what is a butyl cellosolve, just how much sodium hydroxide can be a safe percentage in a product. (ones that are very "active", but damaging, such as Castrol's Super Clean, or some versions of Simple Green, some "locally made brands of such" have a very high percentage of each or both, so live and learn.
Anyone in the business for more than a few years, or read some posts on forums, know that either of the mentioned "name brands" may do some removal of some things very quickly.
But!!!! At what price in the long run? What costs may be to the detailer in regards to their local detailing reputation, etc, just to "get it done quick and out the door"?
Grumpy
