How to Remove Files from the Filesystem in blackberry using Eclipse Plugin

I have just jumped into the Blackberry development arena...

I am trying one example for storing a persistence data into Blackberry file system.

In that I am using following classes :

import net.rim.device.api.system.PersistentObject;
import net.rim.device.api.system.PersistentStore

From using them I am able to persist the data easily...

But now I need to remove it from the file system to experiment with something...

So, to remove them I am trying following option from Eclipse plugin :

Project -> Blackberry -> clean simulator

But once I open this option, it's sh开发者_StackOverflowowing me as disable and giving me some alert like "Please select clean option".

Thanks in advance....

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open the run or debug configuration -->simulator tab-->memory-->check the option reset the file system on startup -->Apply