Last year I was going to do a social shoot, so I grabbed my trusty old Vivtar 283. Tried to turn it on & nothing. Opened it up and the batteries that were in there had exploded. Tossed some new batteries in without cleaning anything, and it wouldn't charge up. I pretty much needed a working flash in about 4 hours from when I discovered this, so I went to one of the camera shops in town, and found a used Vivitar 285 that I purchased, and used for the past year. The 283 just got stuffed into a box and i never used it since. Last night though, After taking a photo, the 285 just fell off of the hot shoe. The plastic foot had cracked and broke off. Anticipating maybe needing a flash again today, I pulled out the 283 and gave it a look. The internal contacts seemed fairly clean, with the residue from the exploded batteries still on the walls. The contacts on the plastic battery holder is where all of the really bad corrosion seems to have taken plan, so I figured that was were problem was in not letting the unit charge. So I used the clean battery pack from the 285 and loaded the 283 with it. It started charging, but the distinct steady sound of the capacitor charging was really erratic, and the whole device started to smelling like battery acid, so I turned it off and pulled the batteries out. Does this behavior just sound like it is caused by the residue still present in the battery chamber and on the contacts? Or some internal malfunction in the unit itself that may have caused the batteries to pop in the first place? If the former, what is a good method to clean the residue out & get it off of the contacts safely? I'd like to get this unit up & running again if possible.