[Steffen]

My routine is:

1. Blower
2. Lens brush
3. Lens pen
4. Blower

strictly in that order. For tough gunk I sometimes use a small amount of lens cleaning fluid or methanol on a microfibre cloth, but I haven't had to do this in a long time.

It helps to clean the barrel and surrounds of the eye lens first with a microfibre cloth.

Cheers
Steffen.