Give it a good vacuuming and see if it works after the bug spray. If it does,
put it in a plastic bag and put it in the freezer for about a week, then leave
it sealed in the plastic bag at room temperature for another two weeks. Then
back in the freezer for another week, back at room temperature for two weeks.
Inspect and clean again, then it should be fine.

This is a very standard museum insect control technique that's easy on
electronics. Not so good for ivory, wax, films, paints on canvas, wood glues
and materials saturated with water, but should do fine on sewing machines.

No, I've never seen a sewing machine infested with cockroaches, but I've seen
telephones, computers, radios, television sets...

Kay (old biologist)