I just picked up a Super Mondia from the early 70's and I just finished stripping all the parts off to begin the cleaning. I took the frame off the stand and noticed there is debris inside the seat stays!!! As I turn the frame around in my hands you can hear it rolling around in there. The pieces sound like they are the size of medium to coarse sand.

The holes near the drops and the holes near the seat clusters seem to be clear, but I can't shake anything out.

Has anyone run across this before? I've worked on dozens of old frames, and sometimes I hear a lone piece of debris rolling around, but never this much. I want it out!!!

Thanks,
Tim