A couple of years ago I bought one for my wife. I inherited after she lost interest in the hobby it was for. Now it is dead. Opened it up and it had two non-standard lithium cells hardwired in. I took it to the battery place and he declined, saying he was trained in replacing lithium batteries but the company would not let him do it because of insurance issues. Sounded like I had brought in an IED.
Dremel would not give a price for replacing the batteries. I would have to ship it along with the charger to them insured, then wait for the dreaded phone call telling me where to leave the money in small, unmarked bills.
My other options were to trash it, call the bomb squad or bury it beside the road at night. Trashed it.