Minimizing size of target RFS on host computer
 

I have RFS which was created by somebody based on whatever requirements. I put this RFS on Compact Flash and was able to to boot kernel I compiled. So far so good. But the problem is - this RFS is huge (500MB), and have bunch of stuff I don't need. Is there a graceful way to reduce size of the target RFS on host computer?

When I run 'rpm -qa' on my target with this RFS I see packages which I definetly don't need. But how could I remove them on my host computer? Or just 'rm' everything in my sight I deem unnecessary? Is there a method of minimizing existing file system, instead of creating a new one from scratch?