personally the best way i have found that is cheap and quick is to:
get the pack of pills, do not remove them yet, but instead turn them foil side down onto a flat surace, and crush them by hitting them with a blunt object, the powder wont break through the foil aslong as they are pressed agaist a flat surface, then carefully hold the packet over a container and push the non foil side outwards into said container this way you dont end up losing much powder and it wont be all the way down the container/cup etc.
then use enough water (doesnt have to be cooled, just use water from the non hot water tap) to just submerge the pills, the less water you use the better as it means less apap will get through, although if you use too little it wont filter right and will turn into a sludgy waste of drugs.
now stir like mad, just do not stop stirring until you are absolutley sure that the codeine will have diffused throughout the mixture, put cling film over the top of the container (to stop anything nasty getting into it, may seem pointless but it takes 10 seconds, its safer and if you have the horror of dropping your container (because the outside of it will be wet) you wont have just lost all of your drugs) then place in the freezer for 15-20 mins, maybe less if you're freezer is particularly cold, you dont have to over kill it, as long as the water gets cold this procedure will work, however you do not want your mixture to freeze as it just puts you back to square one.
once the mixture has gotten nice and chilly wet 2 coffee filters *THEY MUST BE WET WITH COLD WATER* if your filters are dry they will absorb alot of the liquid and will massivley reduce your overall yeild, place the coffee filters inside one another and then place them over a new container and secure them with anything you can, elastic bands are generally best, now pour your mixture from container 1 into container 2 and place in the fridge for 10 mins to filter properly.
once you feel that no more liquid will filter through on its own, carefullly remove the first filter (the one on top) with the bulk of the apap in, still leaving the second filter in the container and gently squeeze any remaining liquid from the 1st filter into the 2nd filter, be careful not to break the filter you are squeezing but really try to get most of your liquid out of it, then let the liquid in the second filter go through, once the second filter has filtered the solution you squeeze into it, just lightly squeeze the second filters liquid into the container holding your hopefully clearish solution.
now for the bit i have always seen missing....
for piece of mind keep both used filters and look into them at the amount of shit you have seperated, that way you will not get freaked out about what if's and think you are dying, keep them until the high has ended if you must just to make you feel safe.
anyways the solution you have in the container should be clear to clearish NOT milky unless its paramol you are using, mix some fruit juice of better yet grapefruit juice if you think it will work, and drink a fairly unpleasent tasting liquid, its not the worst in the world, but its not great, but since you should have used little water, it will be so diluted from the juice you should hardly taste a thing, i personally think it tastes the way attics smell.
enjoy your safer high and reference your filters whenever you need to.
also i dont mean to talk to you like a dumbass (the non hot taps etc.) but the clearer i state it the less your mind can try and find a way to freak you out, and convince you that you did it wrong.
apap is horrible shit, personally you're better off not taking drugs, but if you are going to, always use a cwe, your better of losing a bit of codeine than a bit of liver.