I am doing a reno for my neighbors. They had 4 drafty vinyl windows in their kitchen. The husband sprayed expanding foam on the sides and bottom where the window seals. I need to remove the spray foam without damaging the window. I've tried to lightly scrap it off with no success. I briefly thought about trying a heat gun but I'm too worried about compromising the window. I don't know if there is a chemical that can help with removal or any other method.....other than replacing the windows. They made it very clear replacement is not an option as they are putting the house on the market. HELP!!!!!!