petroleum based nappy rash creams are the ones to avoid with mcn (unless using a liner)
you can tell them apart, becos the petroleum ones, are BARRIER creams, they DON"T RUB INTO THE SKIN

whereas the bottom balm and salves, that are nonpetroleum based DO RUB INTO THE SKIN (not needing liners).

i used a hemp healing bottom balm (hemp oil) and that was fine with teh MCN, Simmons paw paw salve too. (but watch out for the Lucas paw paw salve, that one IS petroleum based).