Remove characteristics from Operating concern

Dear PA gurus

I'd like to remove un-used characteristics and value field from operating concern.

I execute KECM and checked where-used list.

I deleted all customization in the client but still have message that

its characteristics is still used in other clients.

So, do we have to remove all customization from all client in order to remove

from operating concern?

In my DEV environment, we have many clients.

So, it is very much time-consuming to delete all customization from all clients.

I used ECC6.0, so OSS Note 20217 is not for my case.

Yoshi