How to fix battery corrosion in Walkman battery pack?

I opened up my Walkman Pro (WM-D6C) and found that, however long ago I'd last used it, a) I'd left batteries in the battery pack, and b) they corroded. I cleaned it up a bit and tried new batteries, but no luck. (The unit's otherwise functional, as it works with the AC adapter) Here are some photos of the unit: https://imgur.com/a/zBoOyfq Is there a way to remove the corrosion and make this battery pack functional again? Replacements for this pack are not readily available, if my quick scan of Amazon and eBay is any indication.

Thanks for your help.