Can I still use a battery pack that batteries leaked in?

I have those string lights in my room and somehow the batteries inside leaked in the battery pack. A lot looked like it soaked into the battery itself (if possible) because they were discolored. There was evidence of the leak on the rubber part where you close it but the rest of the pack looked dry. Can it still be used with new batteries?
Answers

spacemissing

Clean up the mess and try new cells.

don r

If the batteries are replaceable, remove them, clean the contacts with a swab soaked in vinegar, put in new batteries and test run it.