Found another battery pack with 18650's inside. Hopefully I can get this one without any sparks.
I set that as my goal during the previous harvest but failed on the last cell.
Well it was a case of Deja Vu with this harvest. A spark on the last battery.
At least I got seven more good quality Samsung INR18650-25R M cells to add to my pile of yet to be used 18650s.
Seems like cordless vacuum cleaners are an amazing source for good quality 18650 cells.