how to deal with alloy memory leaks

hi, iam working on alloy project (IOS,android) , and i go this window

<Alloy>
    <Window id="mainWW" onClose="clearMemory">
        <Require src="topbar" id="topBar" />
        <ScrollView id="windowContainer">
        <WebView id="productDesc" />
        </ScrollView>
    </Window>
</Alloy>

function clearMemory(){
 
 $.windowContainer.removeAllChildren();
 $.mainWW.remove($.windowContainer);
 
$.windowContainer = null;
$.topBar = null;
$.productDesc = null;
 
}

when i open the instrument and open the window then closing , the objects still in ram living never gets low

what i should to do for

1) how to remove <Require src="topbar" id="topBar" /> from the window and null it

2) how to null the rest objects (windowContainer,productDesc) and set it to null too ?