Thank you; this page was EXTREMELY helpful. First tried removing loose battery & then pressing down on stuck battery with long screen driver; nothing. Next followed above tips regarding small squirt of WD40 . Later sprinkled baking soda & letting it stand over night. Next kept gently thumping keyboard on a towel which caused plastic battery tube cover to pop out. With screwdriver gently pushed battery spring assembly out of chamber while still attached, removed battery & wiped the entire chamber clean of the corrosion, WD40 & baking soda.
By now was sure the keyboard was dead forever & ready to toss it but reinserted spring assembly & added 2 fresh batteries and tried pairing.
Voila! Never give up. This post is being typed with the trusty Apple keyboard. Amazed that it is so well built that it could take the above abuse that it was subjected too.
Thank you all for the above tips.