My son used to make the Chewbacca sound but he passed away in 2012 at 18 from cancer. I missed that sound because it always made me laugh, so I bought a Chewbacca sound toy and left the batteries in and it corroded. I used this video and IT WORKED! I cannot thank you enough.Ive been cleaning corroded battery contacts this way for years now. One tip I didn't see is to hold devices like remote controls etc upside down when applying the vinegar and alcohol. This prevents it from running down inside and contaminating the circuit boards. Great video.