Hello, I have access to a pretty big telescope, at least when compared to others I've played with. I'm itching to set it up but the mirror is not in great shape. It has been in storage for a long time and there looks to be some corrosion. I was wondering if there is anything I need to be aware of before I try to clean it, or if anyone has any tips? It's 300mm in diameter and the telescope was built in Stockholm in 1997 according to a brass plaque on its mount. I have attached a picture of the corrosion. It's a little hard to tell what you're looking at since it's a mirror but you can see it contrasted on the white background (off white, but center image) of a support strut. There are a few such marks. It's not really mine (a friend of the family's, but he is aware of it's condition and has given permission for us to use it in exchange for storing it :) ), so I don't want to go doing anything that's going to cause damage. Thanks!