BMW Convertible Top Care Questions

[Peter Biernacki <pbiernac@xxxxxxxxxxxxxx>]

Could someone please tell me how often the convertible top on a 1999 E36 
323iC should be washed using the BMW convertible soft top cleaner?
Also, the care kit for the top states to use a sponge or soft brush, can 
someone recommend a good implement? 
How often should the waterproofing agent be applied to the top (i.e.
every time the top is cleaned with the soft top cleaner, or less
frequently)?
Finally, how often should the rear window be cleaned/polished with the
convertible rear window cleaner?

Thanks in advance.

------------------------------