Jumpstarting NiMH batteries that won’t charge

WIN! I had a few NiMH batteries that my charger would not charge. I thought they were broken, but found out that you can sometimes jump charge them a bit and they work again.

So I hooked up an DC adapter set to 12v to them for 2 seconds and then put them into the charger and now they are charging again!

Update: A note for future reference — positive to positive, negative to negative.