We have an older (1890-1900) two story farm house. At some point in its past, foam insulation was injected into the exterior walls (the plugs are plastic, if that helps date it). The foam is "loose" in the walls- we get a lot of air infiltration around electrical boxes. Short of pulling down the lathe and plaster, and removing/redoing the foam, is there any other remedy? I can seal all the wall penetrations, but if there's that much air getting around the foam, I have to questions it's effectiveness anyway.

Second question- a portion of the kitchen (an add on, I believe) sits over a completely sealed area- I have no idea how deep it is. The foundation is concrete block. The floor over this area gets very cold. I have been contemplating knocking a hole or two in the blocks to gain access, and having the area filled with foam, if it's not too deep, or seeing if a contractor could get a long gun in to spray the walls and floor from below if it's too deep to completely fill. Thoughts/comments/suggestions?