Since the ZHPs and M3s come with cloth visors it's actually a little easier. Use a hair drier to heat up the sticker, and start peeling at the corner. Pull gently as the glue melts. If you're good, it should come off as a single piece.
There will be residue in the shape of a sticker left over. What I did to get rid of that was to use a steam press to heat up, and then a towel to lift the glue. Had to repeat that process a few times. Can barely tell the stickers were ever there now