Enamel spray paint accidentally sprayed on mobile home siding...

Try using non acetone nail polish remover or Wd40.

Rubbing or Denatured Alcohol may work....

I would suggest nail polish remover, too.

WD40

I would try cooking oil..

TSP??? I've also used "disolve-all" which is orange oil. It will remove anything, but you have to rinse thoroughly with water after using it.

Paint it over

Xylene is what I use to get rid of already dried paint. They use to sell it where they sell paint.

You have to test with a tiny droplet from a tooth pick first. Note that xylene may melt plastic. My experience with xylene is that if the paint hasn't dried very long, say a day or two, it goes off quite nicely, while old paint is hard to get off.