Paul I would suggest first take the corrector plate off, noting it's orientation. Then I would try Dr Clays cleaning mixture which is safe for corrector plates, if that mixture doesn't work I'm not sure what to suggest. Dr Clays mix has Windex, IPA, Demineralised water and photoflo solution to achieve good cleaning without streaking. I've had the corrector plate of my LX90 and its a simple task, I assume it would be the same for the Celestron. Corrector removal is covered in Jan's LX90 pages
http://m1.aol.com/kewtasheck/corrector.html Dr Clays cleaning recommendations are at
http://www.arksky.org/asoclean.htm I'd also make 100% sure all the fungus is removed from the inside of the OTA. Good Luck.. Once you have done the job I think I have seen some SCT backplate caps that incorporate dessicant holders, might be worth hunting one up.
