The procedure consists of heating the resin coating (8) on a panel sealing strip (7) to a temperature above the coating's vitreous transition temperature (e.g. of 73 - 74 degrees C) but below its viscous flow point of about 190 degrees C. Once the required temperature is reached the coating can be easily removed with a manual scraping tool such as a spatula. The heat can be applied by a hot air gun equipped with a projection on one side that limits its proximity to the surface being treated to about 50 mm. The coating is maintained at a temperature of 90 - 110 degrees C for a minimum of 3 minutes and a maximum of 15 minutes.