Posted by Gary Poyner at 16:30 on 2011 Nov 17
Hold the mirror up to a light source and look through the bottom. You will soon see if it needs re-coating or not, as you will see light shining through the worn area’s. Washing a 12 inch is fairly straightforward, but try not to use any liquid which contains lanolin, as this ‘may’ leave small white marks on the mirror surface. Always use distilled water too.My 51cm mirror is from OO and has Hi-Lux coatings. It’s great! I’ve also compared a 25cm with and without Hi-Lux, and the Hi-Lux wins every time. If you do get the primary done, have the secondary done as well, whether you think it needs doing or not. Good luck,Gary