一尘不染: maintain one's original pure character; as clean [neat] as a (new) pin; be spotlessly clean; free from dust; maintain personal integrity (during chaotic times); not be contaminated by the
干干净净: clean and fresh; neat and tidy; clean as a pin; spick-and-span 短语和例子市中心一尘不染干干净净。 the centre of the city is spotlessly [stainlessly] clean