They could not eradicate them.

Lessons learned:- I really enjoy flipping a house with my own hands- I now know how to eradicate certain pests inside a property- I have gained an incredible amount of knowledge on inspecting a property to make sure it is a sound home Did you work with any real estate professionals (agents, lenders, etc.) that you'd recommend to others?

@Derek Carroll I definitely will vet the dry fog company and make sure the mold is prevented and eradicated.

Bed Bugs:  I WI if the tenants brought the pests into the unit, they are responsible for the eradication for them not you the landlord, if you spent money trying to control them for the tenant, you could add that cost is a suit if you evict, (please seek legal counsel for advice) you will have a struggle with this, but as I said see if you can get a Property Manager to do the eviction, they know how to do it, they know the law, and they know how to act on your behalf in court, you will pay for their services, and plan to retain them after when you place a new tenant, this is what they do for a living, hire a professional!

If someone says they have bedbugs, I will have it tested, and I will have the building eradicated.

Tenant agrees to pay for damages and pest eradication if pest infestation occurs as a result of their action or inaction.

Often this stuff can be easily eradicated with a combination of bleach and water or (better yet) hydrogen peroxide mixed with some water.And, as Adrienne has mentioned, the stuff in the kitchen can be caused by cooking methods of tenants. 

But, we can't eradicate ghetto mentality 100% across society.

Their goal was to eradicate the colony.

Hire a professional pest management company to eradicate the cockroach problem.