On Wednesday, June 17, 2015 at 5:03:14 AM UTC-4, mike wrote:

If the hole is big enough, stick a tiny wire thru for the
connection. I use solid wire-wrap wire for such things, but
a strand from a stranded wire can work.

I just repaired a Snap-On Modis OBDII scanner in this manner. This is a multi-layer board, but fortunately the liquid damage was limited to a top to bottom connection, not an internal one.

Years ago I was given a roll of transformer wire, which is very thin and lacquer coated. This will snake into very small plated through holes and it did perfectly in the scanner. If the scanner were a double layer board, it would have been simple enough to drill a small hole next to the dead feed through, but on a multi layer, that's out of the question. Transformer wire is ideal for pushing through a blackened feed through. Single strands from stranded wire is certainly thin enough, but it won't have the stiffness to push through most plated through holes.