Can't you thread the 510 atty into the 401 charger? If so, heat the case where the brass connector is with a blow dryer or lighter to cause expansion to the case and loosen the glue, thread it into the charger and tug and pull the crap out of it until you get it out. It'll take some time..but, it'll happen. You'll most like likely pull the case off while the atty connector is still threaded into the charger...if this happens, insert the case back onto the connector just enough to unthread it off the charger...hope I explained this right, and hope this helps.