swellon lipo batteries - any idea how to reduce it?

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My 2 Turnigy Nano-tech Ultimate shorty 90c is slightly swollen. My esc is dualsky 870 with vampire 8.5T motor in blinky mode. so they cant draw much.

Any idea how to reduce the swell? Overnight in Fridge/freezer? any old skoool tricks? Or do I have to perform any voodoo rituals dances to reduce the swelling of those batteries or is it bin time for those?

Those batteries has no loss in the performace at all.