[Jenne and Kiwamu]

 We wiped all the test masses with isopropyl alcohol.

They became apparently much cleaner.

(how to)

 At first we prepared the following stuff:

  * syringe

  * isopropyl alcohol 

  * lens papers

  * cleaned scissors

  Then we cut the lens papers into the half by the scissors such that the long side can remain.

This is because that the SOSs have relatively narrow spaces at their optic surfaces for putting a piece of paper. 

   We did vertical and horizontal wiping using the lens paper and appropriate amount of isopropyl alcohol.

Each wiping (vertical and horizontal) requires two or three times trials to appropriately remove dusts.

Amount of isopropyl:

   * vertical 15 [ul]

   * horizontal 10 [ul]

In addition to this, we also used the ionizer gun for blowing big dusts and fiber away from the surface.

(surface inspection)

   Before wiping them, all the test masses had small dusts uniformly distributed on the HR surfaces.

Especially ETMX was quite dirty, many small spots (dusts) were found when we shined the surface with the fiber illuminator.

ETMY was not so bad, only a couple of small dusts were at around the center.  ITMX/Y had several dusts, they were not as dirty as ETMX, but not cleaner than ETMY.

   After we wiped them,  we confirmed no obvious dusts were around the centers of the optics. They looked pretty good !