I used to do it with the dennis.sheppard solution:
viewToUse.setImageResource(0);
it works but it is not documented so it isn’t really clear if it effects something else in the view (you can check the ImageView code if you like, i didn’t).
I think the best solution is:
viewToUse.setImageResource(android.R.color.transparent);
I like this solution the most cause there isn’t anything tricky in reverting the state and it’s also clear what it is doing.