[A/S] Aluminum exterior discoloration

[rross@xxxxxxx]

I have a 1994 360 classic motorhome and noticed that some areas of 
one side of the exterior are showing a whitish discoloration.  I 
emailed Airstream factory service to get their input at to cause of 
this and correction.  Their response was that moisture had probably 
penetrated the clearcoating and that the clearcoating would need to 
be removed and replaced. They also said that this job shold be done 
by a professional. The clear coating on this motorhome is Alumax.  
Does this diagnosis sound reasonable?  Must this job be done by a 
professional as I like to do most of my own work if at all possible?
I would appreciate some input from anyone that has done this job.
Thanks for your help.  Ray Ross