Obiez
Bluelighter
I personally have always left them in. I also use the stem of the plant as well, crushed, all mixed, put it in a rag introduce the rag into a liter of boiling water, let it boil for a while, squeeze the rag as to get the juices out, continue about 4/5 times. You will notice when there is nothing more to drain out once your water and the squeezed out water are the same color. Give it 5 more minutes of boiling, drain and squeeze completely and you have everything you can get out of it. If you have a filter coffee maker, this the perfect guide http://www.erowid.org/plants/poppy/poppy_info4.shtml