Chestnut
I would imagine smoke bombs are the best as they will penetrate every nook and cranny. Just make sure you bomb every room with the doors closed and leave it the correct time. No room for error here. I would say leave the cat in there too, but he might not like it, so better not.
Tell your vet this Broadline stuff doesn't work and ask for a refund. You need to protect that cat or this will happen all over again. πΏ
Please don't leave the cat in the 'bombed rooms'!
If inhaled, the smoke can be very dangerous!
You, other humans, cat, other animals & fish must be removed from rooms prior to treatment (read product labels and instructions) and stay out for prescribed time.
If I remember correctly, you will also have to vent or air out treated rooms prior to humans or animals reoccupying areas.