how do you clean that up

very carefully

I wonder, is this the final stage of the key animation for this particular animator and the cleaner gotta do the "good drawings" by himself? Poor thing

Who's charged to clean anyway in the japanese animation industry? The animation director?

The 2nd Key Animator.

I see thanks. Does it happen often, that a key animator draw roughly like that and a 2nd KA redraw it cleanly? Like, do any "famous" KA actually do only rough? Is this depending on the production context, or are there KA that only animate that way, letting a 2nd KA do the clean drawings?

Also, why is this animator in particular permitted to animate roughly like that? His animation doesn't seem that special to me to allow him to do rough while a second KA uses it as a base to do it better. Is it only a matter of saving time for production?

Sorry for all the questions.

This doesn't actually match up to the scene so it's probably just a rough animation (another example of this kinda thing is Bahi JD's ping pong roughs)

ya i guess it was scrapped before he even managed to take it to 2nd base

This is just a first pass most likely.