Wiktionary
do off
vb. (context obsolete English) To take off (clothing).
Usage examples of "do off".
Therefore, sweetheart, if thou fearest that the King should punish thee for so wounding the poor Christopher of those few days ago, as belike thou deservest it, bid the King do off his raiment, and do thou in likewise, and then there shall be no King to punish, and no King's scather to thole the punishment, but only Christopher and Goldilind, even as they met erewhile on the dewy grass of Littledale.
You just don't age at the same rate here as you do off this planet.
She had no use for the Rebs, she spied on them whenever their loose talk gave her the chance, but she was getting, if not rich, at least well-to-do off them.