[AS2] Best practice for releasing memory

I just wanted to know bout best practices for releasing memory for flash data structures (Mainly when classes are used). What you guys do in general practice and take care?

e.g. I extend a class from MovieClip class and have many data strctures and movieclips within that class. Now when I remove that movieclip will flash automatically remove other children movieclips and data structures? Or I have to remove them for safety…