Strange lines don't disappear

 From:  JTB
278.1 
Michael, a strange thing again.
I make a curve, then revolve 360deg, then use shell command to make that solid that looks like a pot. Then I make a box and use boolean-diff.
Then I see these strange lines. I try to delete everything but the lines don't go away

EDITED: 1 Feb 2007 by JTB