u/Professional_Kiwi506

I just spent so much time taking a backsplash off of my kitchen wall and there was sticky foam residue that I can’t get off.(it’s goes about 10ft across my kitchen) I’ve tried goo gone, alcohol, a heat gun, a rag and water, acetone (I also used a scraper with the products mentioned ) I can’t seem to get it off for the life of me. Everything takes major scrubbing/scraping and I’m getting nowhere. I also don’t want to have to replace the wall. Is there anything else I can try? Any suggestions? Can I sand then paint over this and stick the new backsplash over top? What would be the most effective solution here?