Glass shards in Logic board connector?

I have recently removed a badly-shattered iPad 4 screen, and installed a replacement.

About 5/6ths of the way down the screen, there is an (invisible) horizontal band, running the entire width of the screen, that is completely unresponsive to touch. I have tried two different screens, with the same result.

On close inspection of the sockets where the digitiser ribbon connects with the logic board, I noticed one was slightly cracked and raised, suggesting a stray piece of glass (or other debris) has managed to get stuck in there. There is also evidence of a deformation of the ribbon end, resulting from when I pushed the ribbon into its socket.

Does anyone have any experience of this and could suggest the best way of cleaning out the socket? Should I use compressed air, or isopropyl alcohol, or is there a better method?

All suggestions gratefully received.