frame question about a 76

This may sound silly, but is there a good way to clean dirt from the inside of the factory boxed in frames? Mine has some places where i can tell dirt is trapped inside the frame up to the acess holes in the side, is there a way to wash that stuff out? I was just thinking that the dirt would hold moisture and be even more harmfull to the frame.

Thanks, maybe im just worrying to much.

Steve

 

In the past I have used a pressure washer to blast it out and then used my compressor to blow air through there to dry it. Not sure how else you would go about it.

Mike