Integrating new resource management policies into operating systems (OSes) is an ongoing process. Despite innovative policy proposals being developed, it is unrealistic to widely deploy a new one because it is a difficult, costly and often an impractical endeavor to modify an existing operating system to integrate a new policy. To address this problem, we explore the possibility of using virtual machine technology to incorporate a new policy into an existing OS without the need to make any changes to it. This paper describes FoxyTechnique, which virtualizes physical devices differently from real ones and tricks a guest OS into producing behavior similar to a desired policy. FoxyTechnique has three advantages. First, it allows us to implement a new policy without the need to make any changes to OS kernels. Second, Foxy-based policies are expected to be portable across different operating systems because they are isolated from guest OSes by stable virtual hardware interfaces. Finally, Foxy-based policies sometimes outperform guest OS policies because they can measure performance indicators more accurately than guest OSes. To demonstrate the usefulness of FoxyTechnique, we conducted two case studies, FoxyVegas and FoxyIdle, on the Xen virtual machine monitor. FoxyVegas and FoxyIdle tricked the original Linux and successfully mimicked TCP Vegas and Idletime scheduling, respectively.