This has nothing to do with cleaning the top but is related.
I installed rear speakers at the beginning of the summer, and was using the soft top all summer. The rear speakers made the stereo better, but it wasn't an incredible improvement.
Since I put my hardtop on last night; today on the freeway at 75mph I said, Wow! The rear speakers sound a lot better. I am assuming that the hardtop making the car quieter had a lot to do with his major improvement in sound quality.
So if you want your rear speakers to sound better, get a hardtop, but treat your softtop first!
