[supereliasm]

I've put some bismuth chloride in my moms sink and now there is a tint of black in it. I need to clean this off before she notices! It's fairly obvious, and I really need help.

[Enthalpy]

Scouring powder, plus a sponge that you throw away afterwards, plus arm strength?
The sink will be too clean, so find some benign explanation for having cleaned it.