>> pour a bubble of green in a bath with water and take a bath
>> The baby was eventually somewhat washed, but here the bath
>> I have to give up...

It was chemistry at school. First a stupid decision, then complete helplessness. Any intense oxidizer, from hydrogen peroxide to banal chlorine whitening, would whiten the bathroom. But yes, someone washes the fat with expensive “natural biodegradable” substances, wiping it mechanically, and someone dumbly waters it with alkaline and washes it. Teaching is light.