Dirty Tenant is Causing Mice in Other Units

[Jon Fletcher]

The ground floor tenant in my three-family is absolutely filthy. They had an issue with mice and I paid for an exterminator to lay traps. The exterminator also remarked that the tenant is living in squalor. Now the upstairs tenants are complaining of mice, which isn't fair. How do I broach the subject with my ground floor tenants that they need to do a deep clean and keep their apartment hygienic?