If I get them revived, I'll do any charging near the garage door and have a bucket of dry sand on hand just in case. It's such a shame that Li-Po's have these bad characteristics. I'm always hoping for a new battery technology to come along and put these little fire bombs to rest. My batteries only have a few charge cycles on them but they sat for several years and went into lockout, so my fingers are crossed for a good revival.A steel ammo can is a good plan. Make sure to take out the rubber seal first or you will not be happy if the battery fires off.
Another (more expensive) possibility is a Batt Safe. BAT SAFE LLC | battery safety | Carrollton, TX, USA
Good luck. I hope you revive the battery. I have the same issue with an M2Pro battery. Still massaging it.