I wouldn't recommend power washing the panels if they are at all chalky under the paint. I have saved the texture by using chemical instead of high pressure.
Goof off or easy off are a mixture of xylene/xylol and alcohol for faster evaporation. I don't like the mixture as that has two or more chemicals to worry about their reactions with plastic.
I prefer xylene/xylol to remove paint as it usually does not do terribly weird things to colored plastics. This can include carpeting (always test a spot).
Of course every different kind of paint that has been offered in 40 years each have their own characteristics of removal.
http://en.wikipedia.org/wiki/XyleneI've yet to try the oven cleaner process. Guess I'll have to try that way next time.