obtaining Opium Tar from poppy

[peacemaker]

is it true that obtaining Opium Tar from opium poppy is so easy?


I've found such instructions on erowid:


[...] When the flowers go to seed, scrape the seed pods with a pin. Do it all
around the pod. As you do so, you will see little blobs of white coming
out. Leave the wounds to seep for a few hours.

A couple of hours later, go back and harvest your opium. By now, the white
blobs will have turned into black tar that can be scraped off and collected
on an old, blunt dinner knife or some such.

This really does work, and it is legal to grow the flowers. (at least, it
is in the UK.) However, once you start to scratch them, I suspect that you
become party to a conspiracy to manufacture. Not very clever. So be
careful. [...]

does it work? if it does, can I do it on growing poppies or can I pick them and do it home?