Repair Project Luke ROTJ MR

[JediLightbearer]

Hello all, I am looking for some assistance in repairing an old lightsaber of mine. It is a Master's Replica of Luke's ROTJ saber that was converted by Ultrasabers back in 2008. I have had this guy for years and was given to me by my master. I haven't used it in some time unfortunately but now things have gotten worse. Apparently at some point within the last 2 months, it has suffered from battery corrosion and I'm not sure if the battery pack is salvageable. Even more so, the inner connection inside the hilt has some corrosion as well and I'm uncertain if that has ruined the saber. I also need to possibly re-wire the saber as the power switch no longer works and the only way for it to turn off was to remove the battery pack.
I have no experience in electronics but I am willing to learn to fix this legacy of mine. Any and all assistance would be appreciated.

[firehand10k]

Wow mixed batteries and left in way to long. Pretty much everything that can be done wrong. Just need to try flipping them round backwards for good measure.

Seriously though, clean up the contacts with some vinegar then rinse with baking soda solution, acid to wash base to bring back to neutral. Check to see if the contacts are still solid enough to work then try again with new batteries from the same pack. I'm not familiar with the switch on those but it may need to be replaced. I wouldn't know what to recommend for it without seeing it.