i have two batteries that refuse to charge. can i put them in the freezer or fridge for a couple hours to revive them? or is it time to purchase new?

thanks.

If you run them down too much they become trash. Don't know any revival tricks once they are below 3v per cell.

Putting a battery in the refrigirator won't revive a battery. That technique is used to lengthen the shelf life of a battery, not revive them. And it's only about 5%, so it's really not worth the effort.

If the battery you're speaking of is a Lipo battery, you could put it on a Nicad charger for a few minutes, under supervision. Then put it on the lipo charger. (As long as the voltage ratings are the same for both chargers.)