Numerous models of Cobra handheld radios have a special feature which prevents accidentally charging alkaline batteries.  If alkaline batteries are charged, they will leak!

To prevent charging alkaline batteries, the radio has a separate charge contact which touches the side of the battery.

Alkaline batteries have a plastic wrapper all the way down, so they will not touch the charge contact and will therefore not charge.  

The issue is that other brands of rechargeable batteries also have a full wrapper, and so they too will not charge. The solution is to peel the wrapper from the negative end of the battery.  Use a sharp knife to score all the way around, and then peel off the wrapper so that the battery looks like the picture above.  Do it to all the new batteries.