[alan meehan (Alan)]

I have just recently been given a celestron C8 1983 orange tube scope complete to add to my collection of classic scopes i have cleaned many mirrors and glass before but never come across a correcter plate as bad as this one i have washed in warm slightly detergent water demineralised water
bintel glass cleaner isopropyl alcohol and nothing has removed the mark stain even tried liquid mould remover nope still there has need a solution anyone