Gombessa The piano shop for my last piano suggested Windex for high-gloss polyester. Which I know is usually verboten in forum wisdom, but I used it because it was recommended, and....it's horrible. Do not use Windex. It takes away the glossy surface and really starts to dulls/grays the finish.
OMG!!!!!! I hadn't heard the advice to use Windex. But if a piano dealer recommended it to me, I probably would have used it without question.
Yikes! Glad to know that the car wax rehabilitates it.
Would car wax make existing scratches less obvious? I bought my piano used, and the previous owner I think keep the lid closed and covered with papers and stuff. It's not noticeable most of the time, but when you look at it closely...