I have no idea about "~아 치우고". However there is a most used pattern of "~ 치우고", it is "해 치우고". It is used in case of that some works have to be processed speedly. For example, when you are tired caused by difficult works for a long time, you can say like this "이 일을 빨리 해치우고 쉬고 싶어". This means "I want to have relax time after these works are completed in sooner time." My English expression might be unnatural. ^^