Personally, I put the whole concern through the filter. Just a couple of drops of water sloshed round the jug will loosen it enough to pour it through the filter.
If you've done the crush/dissolve stage properly, then yes, chances are that the sludge is almost all APAP.. ..but it doesn't hurt to filter it anyway. Every drop counts. And if you didn't get much of an effect, then i'd suggest that maybe you lost codeine during the process. ....probably the most important part of the whole cwe process is to make sure your filters have been properly soaked before hand. This way the brew will flow though it, instead of being absorbed into the filter.
I'm a fucktard.
I've read through this thread tons of times in the past but wasn't in the best state when doing it. Mehh, shall try again soon. Toothache like a bitch!