How to clean buildSrc dir from root project in Gradle?

I have multiproject build in the buildSrc dir.

  buildSrc
       ---build
       ---  subProject1
          ----build (2)
       ---  subProject2
           ----build (3)
       ---  subProject3
          ----build  (4)
       ---  subProject4
          ----build  (5)
    config
    gradle
    src
    build (1)

When I am in the root dir of my project I write:

gradle clean

but only build dir of the root project was deleted(marked with 1). How to trigger Gradle to delete all build directories prom buildSrc without to go manually to buildSrc and to write gradle clean.(marked with 2,3,4,5)

There is no way to do this (but you shouldn't ever have to clean buildSrc).