If you are confusing cache memory with a different type memory you might not get the response you are looking for. Misinterrupting terminology can really confuse the issue. You could be talking apples and get an orange response. I'll take a guess at what you may be asking.
Vitual memory may be cleared by simply shutting down your system completely for about 10-20 seconds, then rebooting back into your OS.
Sorry, if I confused you, but I think you may have confused everyone else also.
Fisher of men