I used Windex on an eyepiece one time and cleaned the coating right off.
Just say NO to commercial cleaning products.
You do NOT, as in cannot, remove SCT coatings with windex. Coatings are baked into the glass. You would need sandpaper or sulphuric acid to remove corrector plate coatings. I'll refrain from voicing an opinion about the eyepiece because there are so many decades of production and so many manufacturers, not all of them good.
Here's a document:
How to Clean Your Corrector Plate
Here's a visual disassembly guide:
Disassembly of a C8: Child's Play
p.s. Rod Mollise has been using Windex for decades and he "wrote the book" on SCT ownership. I use Tech Spec Lens Cleaner from Edmund Optics, they know a thing or two about optics.
Edited by gnowellsct, 14 August 2020 - 03:43 PM.