I am making a mm 67 vette convertable, I used some box stock styrene to fill in the trunk area behind the seats. I am practicing the vitagoo filler to patch the plastic. However as I brush the glue on the seams that are around the trunk the lines are disapearing. What would be a good way to cut them back in? I was thinking to use a hobby saw and scrape them in. I intend on painting the car when done. HELP!!!