I would take out all the gars, baggie em then let the humidor sit open for a number of days (depending on where you are in the country... the humidity level of your area... dry area, only a one or two days, more humid, maybe even a week). Close the lid of the humidor, let sit for an hour then get a reading (i hope you have a digital hygrometer... if not, get one). Keep a close eye on it... Get a reading every day.
If both the wood (humidor) and the gars are too moist, it will take too long to get back to 70 just by leaving in the humidor and you risk ruining all the cigars to mold/rot. On the other hand, don't get your humidor tooooo dry or the sudden change in relative humidity will crack the wrappers.
hope this helps. Oh, one last thought, have you seen those crystal sticks that absorb moisture. I have never personally tried one, but maybe you could use one of those. Again, the change in humidity can't be too dramatic too soon, or you will burst/crack the wrappers (yes, unfortunately i speak from experience!)
GOOD LUCK,
Jeff