Primary mirror cleaning

After 4 years of intensive use my primary mirror of the 200mmF5 Newtonian is becoming very dirty. There was even a piece of hay stuck to it. I was not able to get all dust particles off, but it is a major improvement.

 Here is the primary mirror before cleaning, you see the piece of hay stuck to it (I have no idea how it ever came there in the first place....)

 Rinsing the mirror thoroughly for 10 minutes already does a lot of good work.

After that I let it rest in the sink for 1 hour under lukewarm water with 1 drop of cleaning agent. After that I used cotton to clean in from the outside in, under absolutely no pressure. After that a few minutes of rinsing. This is the final result. You still see some particle, but it is a major improvement.