Network-aware research applications increasingly require the capability to program network functions in order to satisfy particular requirements, such as end-to-end visibility, etc. For the successful verification of network-aware research applications, the construction and operation of experimental testbeds over international research and education (R&E) networks is of strategic importance. Supporting experimental testbeds over production international R&E networks exposes the production environment to potential risks, and increased complexity. To mitigate risks operating experimental testbeds, the AmLight project implemented a validation process, then developed and deployed the Testbed Sanitizer. Our experiences and findings using both the validation process and the Testbed Sanitizer and future work towards the support of experimental testbeds in a production R&E environment are described.