Decontamination

Good morning
I would talk about your experience for decontamination of manufacturing department.
In fact in my Plant, our Customer would want to manufacture a new product. This manufacturing would be made in department in which it was dedicated to an other manufacturing of a beta- lactam product.
We explained that for a long time (years), the department was stopped and all tanks were preserved with solution caustic soda + water.
Question is, do we need to decontaminate the floor? (… to show that there isn’t any residual of beta -lactam!).
Have you experience in this field?
How do we perform this decontamination?
What are the activities to follow ? (for example, quality documentation, sampling, analyses, ….)

Thank you in advance
Emanuele