My renters were very dirty too and left us with about a million roaches, they were crawling on the walls, floors, ceiling, inside cabnets, stove, oven, bathrooms...everywhere.
I walked in to inspect and just backed out again and called around for exterminators who would come out before "next week sometime"
First treatment knocked out quite a few and he put down sticky traps that filled up over the next week, a follow up treatment before painting got more but still showing up in sticky traps, I am having them come out for another followup spray before doing final cleanup so we can get it rented.
get a company that will come out on a regular basis, at least 4 times a year or you will have the same problem after each renter.
You cannot use boric acid on a rent house without cleaning it out before the renters move in and if you are like me then you don't want to wait a few months between renters.
Good luck
I walked in to inspect and just backed out again and called around for exterminators who would come out before "next week sometime"
First treatment knocked out quite a few and he put down sticky traps that filled up over the next week, a follow up treatment before painting got more but still showing up in sticky traps, I am having them come out for another followup spray before doing final cleanup so we can get it rented.
get a company that will come out on a regular basis, at least 4 times a year or you will have the same problem after each renter.
You cannot use boric acid on a rent house without cleaning it out before the renters move in and if you are like me then you don't want to wait a few months between renters.
Good luck