A cold water extraction won't get gauif out, unfortunately its very water soluble even when cold. Stuff that has a lot of guaif is tainted beyond the control of the common user.
I made the mistake of ignoring this with cherritussin AC which is a codeine/gauif syrup. I ended up violently vomiting for hours on end and felt like my stomach turned inside out.
If you want to use this stuff no one can stop you but in my opinion a codeine high isn't worth the possibility of vomiting for 4 hours straight, kinda kills the high.