Seal them off with metal mesh to prevent the squirrels from making their way back in.
Squirrels in my walls and ceiling.
Above all check every inch of the walls and ceiling for potential access holes.
But squirrels can get almost anywhere in the architecture of a house the eaves the walls and the ceiling the gap between the 1st and 2nd floor for example or a drop ceiling or a ceiling with a flat roof and no attic gap etc.
Find the entry points make sure the young are removed fix all secondary entry areas mount traps on the main hole repair damages.
The principles for how to get squirrels out of your walls or how to get squirrels out of your house anywhere from the soffits to the eaves or ceiling are the same as for the attic.
Baby squirrels in my walls once baby squirrels are born in your walls they can be very problematic to deal with usually you have two options you can have a animal removal company come in and cut the wall to gain access to the nest site or you can wait the 6 to 8 weeks until the babies are fully able to climb from the wall cavaity.
It is imperative for them to chew in order to grind down their constantly growing teeth.
Because squirrels enter through the roof line according to the new york times they almost always make themselves at home within the walls or ceiling of the attic.