How to clean a reflector mirror

It is not a fearsome job. You will need some cotton balls, and demineralised water. Remember though the mirror does not have to be pristine clean to give excellent performance. Most of the time a mirror has not lost more than 1-2% even though it may look a bit dirty. Unless you are really unhappy with it, don't go ahead.

Take the mirror cell from the scope, and then carefully remove the mirror claws, which will not be tight. Carefully lift the mirror (they are heavy) and stand it in the kitchen sink on edge, on a rag or sponge.

Rinse the mirror surface with cold water from the tap, running medium hard, while turning the mirror to reach all parts. Don't lose your hold on it.

Put in the sink plug and lay the mirror down flat, reflective face up. Fill the sink with luke-warm water to about 1 cm (1/2 inch) over the surface, and add a dash of dish detergent and swirl to mix, but don't touch the mirror surface.

Take a cotton ball and dip it in the water, then holding the ball by one end, and using only the weight of the cotton ball with no finger pressure, stroke the mirror surface from the centre to the outer edge. Do not go round and round in circles. Repeat this right round the mirror, using a new cotton ball every few strokes (some say EVERY stroke).

The stand the mirror on edge again and drain the water out. Using demineralised water straight from the container, rinse the mirror surface thoroughly, and lay it flat on a towel, reflective face up, to dry. You can blot large blobs of water with the very tip of a folded tissue, but demineralised water should dry with no mark. Do not touch the surface after this.

You may see greasy fingerprints left there. If they are bad, repeat the above procedure just in those areas, but just before filling the sink with lukewarm water and detergent, stroke these spots with a cotton ball soaked in half metho/half demineralised water. Never apply more pressure than the weight of the cotton ball.