Best way i found which may take you a good month before removing is, Use a razor or knife cut away the hard bark till you get to the white meat. Make a Ring with your knife and depending on the size another ring below that. Example: a air layer with 1/2 in diameter on stem space the rings about 4 to 5in, and strip away the bark. Then get you some spagma moss wet preferred even better soaked in miracle gro. Then if you have some root tone rub that on the white meat. Now get a handful of that wet spagma moss and wrap it around the wound you just made (Good size hand full). Then wrap that in aluminum foil and twist the ends to secure. Best placed air layers are the ones that get some sun. In a month or so you will have plenty roots for potting. I did one once the stem was 2 1/2 in round lol was a tree when i removed it, Looked like a aluminum basketball when it was wraped.