I just learnt here https://rxsecure.umaryland.edu/courses/PHAR535/lecture_handouts/Liquids/Liquids_Lec_Handout.pdf (https://rxsecure.umaryland.edu/courses/PHAR535/lecture_handouts/Liquids/Liquids_Lec_Handout.pdf)
that 1gm of codeine phosphate is soluble in 325mLs alcohol. This means you would have to dissolve your pfed/codeine in 6.5mLs of alcohol and filter it to get the codeine out (all but 20mgs would be left.) Like as if you could do that ::)