i've never used the jar method, what i do is..
take them down, cut leaves off, and hang them by their branches, then after a few days (all depends on temp, and how fast they dry) cut the buds off the branches, and put them in a black plastic bag to sweat them (usually up the temp a little in room (just cause i'm very impatient)
then lay out on a screen and dry again, then repeat untill you get desired results.
i'd suggest maybe try to sweat them (though if they're too dry, they may not have anything to sweat out)
i don't know if this is a good idea, but if you have any leaf that still has some moisture (and hasn't gone bad) you could maybe put a few leafs in with the buds in a plastic bag and try to get the buds to draw some moisture from them.. i don't know if this will work though.. or if it's even possible, as i don't how long ago you cropped, so the leaves may be garbage now.
*once again, i've never tried this, so don't know if it's a good idea/bad idea, or if it will even work, so try at your own risk, but i'd wait for some other suggestions first
good luck.