You might be able to use the Data Repair API, but that comes with additional costs... it likely isn't worth that...
I've never purged data myself, I keep our dev/qa suite for testing data, and prod for fully tested / vetted releases...
If garbage data does go into prod, I actually have set up my suites with a "Prod" physical suite, and a "Prod - Clean" virtual suite. Basically, I have a "clean" segment that will clean up / remove garbage data... all our reports are made using the Clean Virtual Suite (and since I have a multiple virtual suites to separate out our individual sites, each one of those also includes the "clean segment")