Try geting the car PROFESSIONALY valeted .. .they have kick ass cleaning machines that can do the impossible (almost) some of them have steam etc...

If you doubt the value of the pro machine i was shown a car that had been in an accident and the driver had lost several pint of blood into the seat...which had then dried....a pro valet had got it out so you couldn't tell...

with regard to the sunroof (never seen one out so just going off your description) is it not worth having the nipple welded back on..a good welder can weld ally as easy as steel with the right tackle...