Why exactly were sinks put there in the first place, there are no taps for us to do any washing up so it can only be for pouring unwanted liquids down and what liquids do we have on an a/c........Tea and coffee.
Sorry but i pour it down there if it gets blocked then sort out the problem. (sorry engineers) I am not taking pots into a toilet and contaminating them. Or give us something that we can put down the drain that will clear any bits that will cause a blockage if left to build up.
6