One of these units. (this is also the same unit I used to repair the polyethlyene front valances)
http://www.urethanesupply.com/Airless-Welders-1/
I used the ABS sticks and just kept applying, sanding and reapplying. I then used the SEM Landau black and misted that on to blend in the color. Completely invisible now. Did I say how much I love that SEM Landau black spray dye????