Yes you can. Up to 24 in 24 hours. But as has been stated, you would lose all of the bonus you accumulate each time you leave
24 every 24 hours but you loose ur bonus once you leave an eb midway. Like moose said not a sound method.
Well, you could, but then you would lose your previous bonus you had before u quit. However, Id u are afraid of losing, an it is very important, I would probably sacrifice the former Chrystal's and reward for more damage on the eb.
answer that has already been answered but clarifying prior to lock: You can use up to 24 xtals in a 24 hr period... you can use 6 xtals per epic battle.... if you leave the epic after using 6 xtals, you also lose the completion bonus (up to the the point you left). When you rejoin, you can use 6 more crystals. But remember- you lost the completion bonus from the time you spent hitting on the eb for the first six. You can do this four times per day /lock