My Telescope is bought in 2008.During this time I made some mistakes in maintaining the mirror because I did not knew at that moment how to proceed, and for which I will enumerate some mistakes had to be careful.
1. First, the mirror of a Newtonian is not to be touched with any object, not even with cleaning sticks fot your ears, or other materials.Mirrors have a long life, as long as they are not touched or exposed to unnecessary abuse, such as buffers or cleaning solutions.
2. Do not blow it on its surface, no matter how dusty it is.You can use a vacuum but take great care not to hit by mistake the surface of the mirror
3.Thirdly, be careful when you take off the mirror from the tube, not to drop face down, being quite heavy.
4. The telescope must be kept always with protective cover when not working with it.The cover prevents dust and it is preferable that the outlet for observations to be made in an area away from traffic with cars, or in a dusty environment such as in certain summer periods.
There are plenty of sites with instructions for cleaning the mirror, the only thing I would add is to not do too this often – little dust has no impact on optical performance, but the scratches caused by careless handling can do this . modern mirrors takes many years to degrade. Often looks dirty, but you should not clean yhe mirror until there is a real impact in observation. This will not happen if you are a good observer.