You don’t really want to try to delete performance data yourself. The are in a normalized file system with multiple members across many files. If you Go Perform then option 2, collect performance data then 2 again, configure performance collection, you will be able set the retention period by number of hours or days and the system will purge old collections for you.
Without knowing how you have it configured, it’s impossible to say. In general, review your performance collection configuration in order to learn how your data is organized. The naming convention might be most useful, particularly for the members that get created. Then construct the appropriate DLTPFRDTA command string(s) to delete the member(s) that you no longer want.
Potentially useful commands are GO PERFORM to use a menuing system to review your stuff, DSPPFRDTA to see lists of members, DLTPFRDTA to delete members that you choose.
If you understand the structure, you can retrieve a list of members from a performance data file that you use and compare their creation dates against your criteria. Then issue DLTPFRDTA for the member names that are no longer wanted. The member names will be consistent across all of the various performance data files, so the names of members is what’s important.
As DanD alluded to, you won’t be issuing DLTF nor RMVM commands directly. Use the commands supplied by Performance Tools.