Richard,
To answer your question "How difficult is it to keep a car clean in Jakarta", the answer is; very easy!
If you can afford to buy a car here then you can certainly afford to pay the £2 it will cost you to get someone to wash and leather the car down for you. Alternatively, many people employ a driver here, (average salary £200 per month), and it would be part of his responsibilities to wash the car every day! My driver polishes the car twice a month!! I would worry that it was eroding the paint away if it were my car (Company owned vehicle and Company instruction that the car be polished twice per month!).
Cars get extremely dirty here. Dust and pollution like you wouldn't believe! Also, given the extreme traffic congestion (macet) vehicles spend a lot longer on the road than they need to.
I am sure my friend Pak Oweeyman will agree.
