So in his case he ended up replacing the battery because he couldn't source a replacement part he needed, but he's still got the old battery in case he can get his hands on replacement contacts. Sounds like he wouldn't recommend the grease approach, it did buy him some time but also caused a worse problem later via the arcing. He also said he did maintenance on the battery lock/latch to get it to jiggle less.

Sorry for not having more specifics!