HIGHLY recommended that you use a micron filter, not just a piece of cotton, when IV'ing pills.
And I would suggest only IV'ing the 30mg roxies, nothing smaller, if even that. I'm not into the pill IV thing. Mine go up my nose.
I don't have experience with the fentanyl patches (I don't know if you accidentally misspelled the title of your post or not), but I believe there's a technique somewhere of cutting it into quarters and putting them between your cheek and gums.