Did it involve the camera contacts as well? OK using one wet bud for all of the contacts, important to go through at least a fresh dry area of bud or a fresh bud when trying to get rid of any re-arranged residue to prevent residue from one place being re-applied elsewhere. Isopropyl alcohol doesn't destroy the muck, it just turns it into a slurry until such time as the alcohol evaporates, when the hope is that what muck is left is somewhere harmless, either flushed away, on the drying bud or off to the side.
Gold plated contacts usually need very little contact pressure as gold is extremely resistant to reacting with anything that is airbourne, so any poor contact must be the result of a layer having been deposited.
As a side note, there was a batch of reed relay inserts that had a high failure rate. It was traced to the manufacturer having used an unplated vessel to melt the gold that the reeds were to be dipped in. The resulting gold plating contained impurities, enough to affect contact performance even though they were operating in an atmosphere of (probaly) pure nitrogen.
If the packing pece works, one of two things, either the contact pressure has been increased, or the contacts have been moved to a place where they make contact. Three things. The increase in pressure "might" be causing a poor connection elsewhere to make, either in the battery or camera, but probably inside the battery.