The ability itself works, but the animations and associated system message is broken.

The animation is broken because sometimes it doesn't go off.

The system message is broken because it says the wrong thing sometimes.

How the ability works:

When you use clean slate, it is supposed to reset your progress bar while keeping your durability and quality. This allows you greater chance to make HQ materials.

When it succeeds, the above occurs. Your progress reduces to 0% accompanied by a message that says "progress increases by -80%" or something.

When it fails, nothing should happen.